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<a name="1" href="#1">1</a>   <em class="jxr_comment">/*</em>
<a name="2" href="#2">2</a>   <em class="jxr_comment"> * Licensed to the Apache Software Foundation (ASF) under one or more</em>
<a name="3" href="#3">3</a>   <em class="jxr_comment"> * contributor license agreements.  See the NOTICE file distributed with</em>
<a name="4" href="#4">4</a>   <em class="jxr_comment"> * this work for additional information regarding copyright ownership.</em>
<a name="5" href="#5">5</a>   <em class="jxr_comment"> * The ASF licenses this file to You under the Apache License, Version 2.0</em>
<a name="6" href="#6">6</a>   <em class="jxr_comment"> * (the "License"); you may not use this file except in compliance with</em>
<a name="7" href="#7">7</a>   <em class="jxr_comment"> * the License.  You may obtain a copy of the License at</em>
<a name="8" href="#8">8</a>   <em class="jxr_comment"> * </em>
<a name="9" href="#9">9</a>   <em class="jxr_comment"> *      <a href="http://www.apache.org/licenses/LICENSE-2.0" target="alexandria_uri">http://www.apache.org/licenses/LICENSE-2.0</a></em>
<a name="10" href="#10">10</a>  <em class="jxr_comment"> * </em>
<a name="11" href="#11">11</a>  <em class="jxr_comment"> * Unless required by applicable law or agreed to in writing, software</em>
<a name="12" href="#12">12</a>  <em class="jxr_comment"> * distributed under the License is distributed on an "AS IS" BASIS,</em>
<a name="13" href="#13">13</a>  <em class="jxr_comment"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</em>
<a name="14" href="#14">14</a>  <em class="jxr_comment"> * See the License for the specific language governing permissions and</em>
<a name="15" href="#15">15</a>  <em class="jxr_comment"> * limitations under the License.</em>
<a name="16" href="#16">16</a>  <em class="jxr_comment"> */</em> 
<a name="17" href="#17">17</a>  
<a name="18" href="#18">18</a>  <strong class="jxr_keyword">package</strong> org.apache.commons.logging;
<a name="19" href="#19">19</a>  
<a name="20" href="#20">20</a>  
<a name="21" href="#21">21</a>  <strong class="jxr_keyword">import</strong> java.io.BufferedReader;
<a name="22" href="#22">22</a>  <strong class="jxr_keyword">import</strong> java.io.FileOutputStream;
<a name="23" href="#23">23</a>  <strong class="jxr_keyword">import</strong> java.io.IOException;
<a name="24" href="#24">24</a>  <strong class="jxr_keyword">import</strong> java.io.InputStream;
<a name="25" href="#25">25</a>  <strong class="jxr_keyword">import</strong> java.io.InputStreamReader;
<a name="26" href="#26">26</a>  <strong class="jxr_keyword">import</strong> java.io.PrintStream;
<a name="27" href="#27">27</a>  <strong class="jxr_keyword">import</strong> java.lang.reflect.InvocationTargetException;
<a name="28" href="#28">28</a>  <strong class="jxr_keyword">import</strong> java.lang.reflect.Method;
<a name="29" href="#29">29</a>  <strong class="jxr_keyword">import</strong> java.net.URL;
<a name="30" href="#30">30</a>  <strong class="jxr_keyword">import</strong> java.security.AccessController;
<a name="31" href="#31">31</a>  <strong class="jxr_keyword">import</strong> java.security.PrivilegedAction;
<a name="32" href="#32">32</a>  <strong class="jxr_keyword">import</strong> java.util.Enumeration;
<a name="33" href="#33">33</a>  <strong class="jxr_keyword">import</strong> java.util.Hashtable;
<a name="34" href="#34">34</a>  <strong class="jxr_keyword">import</strong> java.util.Properties;
<a name="35" href="#35">35</a>  
<a name="36" href="#36">36</a>  
<a name="37" href="#37">37</a>  <em class="jxr_javadoccomment">/**</em>
<a name="38" href="#38">38</a>  <em class="jxr_javadoccomment"> * &lt;p&gt;Factory for creating {@link Log} instances, with discovery and</em>
<a name="39" href="#39">39</a>  <em class="jxr_javadoccomment"> * configuration features similar to that employed by standard Java APIs</em>
<a name="40" href="#40">40</a>  <em class="jxr_javadoccomment"> * such as JAXP.&lt;/p&gt;</em>
<a name="41" href="#41">41</a>  <em class="jxr_javadoccomment"> * </em>
<a name="42" href="#42">42</a>  <em class="jxr_javadoccomment"> * &lt;p&gt;&lt;strong&gt;IMPLEMENTATION NOTE&lt;/strong&gt; - This implementation is heavily</em>
<a name="43" href="#43">43</a>  <em class="jxr_javadoccomment"> * based on the SAXParserFactory and DocumentBuilderFactory implementations</em>
<a name="44" href="#44">44</a>  <em class="jxr_javadoccomment"> * (corresponding to the JAXP pluggability APIs) found in Apache Xerces.&lt;/p&gt;</em>
<a name="45" href="#45">45</a>  <em class="jxr_javadoccomment"> *</em>
<a name="46" href="#46">46</a>  <em class="jxr_javadoccomment"> * @author Craig R. McClanahan</em>
<a name="47" href="#47">47</a>  <em class="jxr_javadoccomment"> * @author Costin Manolache</em>
<a name="48" href="#48">48</a>  <em class="jxr_javadoccomment"> * @author Richard A. Sitze</em>
<a name="49" href="#49">49</a>  <em class="jxr_javadoccomment"> * @version $Revision: 593798 $ $Date: 2007-11-10 18:40:43 +0100 $</em>
<a name="50" href="#50">50</a>  <em class="jxr_javadoccomment"> */</em>
<a name="51" href="#51">51</a>  
<a name="52" href="#52">52</a>  <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">abstract</strong> <strong class="jxr_keyword">class</strong> <a href="../../../../org/apache/commons/logging/LogFactory.html">LogFactory</a> {
<a name="53" href="#53">53</a>      <em class="jxr_comment">// Implementation note re AccessController usage</em>
<a name="54" href="#54">54</a>      <em class="jxr_comment">//</em>
<a name="55" href="#55">55</a>      <em class="jxr_comment">// It is important to keep code invoked via an AccessController to small</em>
<a name="56" href="#56">56</a>      <em class="jxr_comment">// auditable blocks. Such code must carefully evaluate all user input</em>
<a name="57" href="#57">57</a>      <em class="jxr_comment">// (parameters, system properties, config file contents, etc). As an </em>
<a name="58" href="#58">58</a>      <em class="jxr_comment">// example, a Log implementation should not write to its logfile</em>
<a name="59" href="#59">59</a>      <em class="jxr_comment">// with an AccessController anywhere in the call stack, otherwise an</em>
<a name="60" href="#60">60</a>      <em class="jxr_comment">// insecure application could configure the log implementation to write</em>
<a name="61" href="#61">61</a>      <em class="jxr_comment">// to a protected file using the privileges granted to JCL rather than</em>
<a name="62" href="#62">62</a>      <em class="jxr_comment">// to the calling application.</em>
<a name="63" href="#63">63</a>      <em class="jxr_comment">//</em>
<a name="64" href="#64">64</a>      <em class="jxr_comment">// Under no circumstance should a non-private method return data that is</em>
<a name="65" href="#65">65</a>      <em class="jxr_comment">// retrieved via an AccessController. That would allow an insecure app</em>
<a name="66" href="#66">66</a>      <em class="jxr_comment">// to invoke that method and obtain data that it is not permitted to have.</em>
<a name="67" href="#67">67</a>      <em class="jxr_comment">//</em>
<a name="68" href="#68">68</a>      <em class="jxr_comment">// Invoking user-supplied code with an AccessController set is not a major</em>
<a name="69" href="#69">69</a>      <em class="jxr_comment">// issue (eg invoking the constructor of the class specified by </em>
<a name="70" href="#70">70</a>      <em class="jxr_comment">// HASHTABLE_IMPLEMENTATION_PROPERTY). That class will be in a different</em>
<a name="71" href="#71">71</a>      <em class="jxr_comment">// trust domain, and therefore must have permissions to do whatever it</em>
<a name="72" href="#72">72</a>      <em class="jxr_comment">// is trying to do regardless of the permissions granted to JCL. There is</em>
<a name="73" href="#73">73</a>      <em class="jxr_comment">// a slight issue in that untrusted code may point that environment var</em>
<a name="74" href="#74">74</a>      <em class="jxr_comment">// to another trusted library, in which case the code runs if both that</em>
<a name="75" href="#75">75</a>      <em class="jxr_comment">// lib and JCL have the necessary permissions even when the untrusted</em>
<a name="76" href="#76">76</a>      <em class="jxr_comment">// caller does not. That's a pretty hard route to exploit though.</em>
<a name="77" href="#77">77</a>  
<a name="78" href="#78">78</a>  
<a name="79" href="#79">79</a>      <em class="jxr_comment">// ----------------------------------------------------- Manifest Constants</em>
<a name="80" href="#80">80</a>  
<a name="81" href="#81">81</a>      <em class="jxr_javadoccomment">/**</em>
<a name="82" href="#82">82</a>  <em class="jxr_javadoccomment">     * The name (&lt;code&gt;priority&lt;/code&gt;) of the key in the config file used to </em>
<a name="83" href="#83">83</a>  <em class="jxr_javadoccomment">     * specify the priority of that particular config file. The associated value </em>
<a name="84" href="#84">84</a>  <em class="jxr_javadoccomment">     * is a floating-point number; higher values take priority over lower values.</em>
<a name="85" href="#85">85</a>  <em class="jxr_javadoccomment">     */</em>
<a name="86" href="#86">86</a>      <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> String PRIORITY_KEY = <span class="jxr_string">"priority"</span>;
<a name="87" href="#87">87</a>  
<a name="88" href="#88">88</a>      <em class="jxr_javadoccomment">/**</em>
<a name="89" href="#89">89</a>  <em class="jxr_javadoccomment">     * The name (&lt;code&gt;use_tccl&lt;/code&gt;) of the key in the config file used </em>
<a name="90" href="#90">90</a>  <em class="jxr_javadoccomment">     * to specify whether logging classes should be loaded via the thread </em>
<a name="91" href="#91">91</a>  <em class="jxr_javadoccomment">     * context class loader (TCCL), or not. By default, the TCCL is used.</em>
<a name="92" href="#92">92</a>  <em class="jxr_javadoccomment">     */</em>
<a name="93" href="#93">93</a>      <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> String TCCL_KEY = <span class="jxr_string">"use_tccl"</span>;
<a name="94" href="#94">94</a>  
<a name="95" href="#95">95</a>      <em class="jxr_javadoccomment">/**</em>
<a name="96" href="#96">96</a>  <em class="jxr_javadoccomment">     * The name (&lt;code&gt;org.apache.commons.logging.LogFactory&lt;/code&gt;) of the property </em>
<a name="97" href="#97">97</a>  <em class="jxr_javadoccomment">     * used to identify the LogFactory implementation</em>
<a name="98" href="#98">98</a>  <em class="jxr_javadoccomment">     * class name. This can be used as a system property, or as an entry in a</em>
<a name="99" href="#99">99</a>  <em class="jxr_javadoccomment">     * configuration properties file.</em>
<a name="100" href="#100">100</a> <em class="jxr_javadoccomment">     */</em>
<a name="101" href="#101">101</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> String FACTORY_PROPERTY =
<a name="102" href="#102">102</a>         <span class="jxr_string">"org.apache.commons.logging.LogFactory"</span>;
<a name="103" href="#103">103</a> 
<a name="104" href="#104">104</a>     <em class="jxr_javadoccomment">/**</em>
<a name="105" href="#105">105</a> <em class="jxr_javadoccomment">     * The fully qualified class name of the fallback &lt;code&gt;LogFactory&lt;/code&gt;</em>
<a name="106" href="#106">106</a> <em class="jxr_javadoccomment">     * implementation class to use, if no other can be found.</em>
<a name="107" href="#107">107</a> <em class="jxr_javadoccomment">     */</em>
<a name="108" href="#108">108</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> String FACTORY_DEFAULT =
<a name="109" href="#109">109</a>         <span class="jxr_string">"org.apache.commons.logging.impl.LogFactoryImpl"</span>;
<a name="110" href="#110">110</a> 
<a name="111" href="#111">111</a>     <em class="jxr_javadoccomment">/**</em>
<a name="112" href="#112">112</a> <em class="jxr_javadoccomment">     * The name (&lt;code&gt;commons-logging.properties&lt;/code&gt;) of the properties file to search for.</em>
<a name="113" href="#113">113</a> <em class="jxr_javadoccomment">     */</em>
<a name="114" href="#114">114</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> String FACTORY_PROPERTIES =
<a name="115" href="#115">115</a>         <span class="jxr_string">"commons-logging.properties"</span>;
<a name="116" href="#116">116</a> 
<a name="117" href="#117">117</a>     <em class="jxr_javadoccomment">/**</em>
<a name="118" href="#118">118</a> <em class="jxr_javadoccomment">     * JDK1.3+ &lt;a href="<a href="http://java.sun.com/j2se/1.3/docs/guide/jar/jar.html" target="alexandria_uri">http://java.sun.com/j2se/1.3/docs/guide/jar/jar.html</a>#Service%20Provider"&gt;</em>
<a name="119" href="#119">119</a> <em class="jxr_javadoccomment">     * 'Service Provider' specification&lt;/a&gt;.</em>
<a name="120" href="#120">120</a> <em class="jxr_javadoccomment">     * </em>
<a name="121" href="#121">121</a> <em class="jxr_javadoccomment">     */</em>
<a name="122" href="#122">122</a>     <strong class="jxr_keyword">protected</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> String SERVICE_ID =
<a name="123" href="#123">123</a>         <span class="jxr_string">"META-INF/services/org.apache.commons.logging.LogFactory"</span>;
<a name="124" href="#124">124</a> 
<a name="125" href="#125">125</a>     <em class="jxr_javadoccomment">/**</em>
<a name="126" href="#126">126</a> <em class="jxr_javadoccomment">     * The name (&lt;code&gt;org.apache.commons.logging.diagnostics.dest&lt;/code&gt;) </em>
<a name="127" href="#127">127</a> <em class="jxr_javadoccomment">     * of the property used to enable internal commons-logging</em>
<a name="128" href="#128">128</a> <em class="jxr_javadoccomment">     * diagnostic output, in order to get information on what logging</em>
<a name="129" href="#129">129</a> <em class="jxr_javadoccomment">     * implementations are being discovered, what classloaders they </em>
<a name="130" href="#130">130</a> <em class="jxr_javadoccomment">     * are loaded through, etc.</em>
<a name="131" href="#131">131</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="132" href="#132">132</a> <em class="jxr_javadoccomment">     * If a system property of this name is set then the value is</em>
<a name="133" href="#133">133</a> <em class="jxr_javadoccomment">     * assumed to be the name of a file. The special strings</em>
<a name="134" href="#134">134</a> <em class="jxr_javadoccomment">     * STDOUT or STDERR (case-sensitive) indicate output to</em>
<a name="135" href="#135">135</a> <em class="jxr_javadoccomment">     * System.out and System.err respectively.</em>
<a name="136" href="#136">136</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="137" href="#137">137</a> <em class="jxr_javadoccomment">     * Diagnostic logging should be used only to debug problematic</em>
<a name="138" href="#138">138</a> <em class="jxr_javadoccomment">     * configurations and should not be set in normal production use.</em>
<a name="139" href="#139">139</a> <em class="jxr_javadoccomment">     */</em>
<a name="140" href="#140">140</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> String DIAGNOSTICS_DEST_PROPERTY =
<a name="141" href="#141">141</a>         <span class="jxr_string">"org.apache.commons.logging.diagnostics.dest"</span>;
<a name="142" href="#142">142</a> 
<a name="143" href="#143">143</a>     <em class="jxr_javadoccomment">/**</em>
<a name="144" href="#144">144</a> <em class="jxr_javadoccomment">     * When null (the usual case), no diagnostic output will be</em>
<a name="145" href="#145">145</a> <em class="jxr_javadoccomment">     * generated by LogFactory or LogFactoryImpl. When non-null,</em>
<a name="146" href="#146">146</a> <em class="jxr_javadoccomment">     * interesting events will be written to the specified object.</em>
<a name="147" href="#147">147</a> <em class="jxr_javadoccomment">     */</em>
<a name="148" href="#148">148</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> PrintStream diagnosticsStream = <strong class="jxr_keyword">null</strong>;
<a name="149" href="#149">149</a>     
<a name="150" href="#150">150</a>     <em class="jxr_javadoccomment">/**</em>
<a name="151" href="#151">151</a> <em class="jxr_javadoccomment">     * A string that gets prefixed to every message output by the</em>
<a name="152" href="#152">152</a> <em class="jxr_javadoccomment">     * logDiagnostic method, so that users can clearly see which</em>
<a name="153" href="#153">153</a> <em class="jxr_javadoccomment">     * LogFactory class is generating the output.</em>
<a name="154" href="#154">154</a> <em class="jxr_javadoccomment">     */</em>
<a name="155" href="#155">155</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> String diagnosticPrefix;
<a name="156" href="#156">156</a>     
<a name="157" href="#157">157</a>     <em class="jxr_javadoccomment">/**</em>
<a name="158" href="#158">158</a> <em class="jxr_javadoccomment">     * &lt;p&gt;Setting this system property </em>
<a name="159" href="#159">159</a> <em class="jxr_javadoccomment">     * (&lt;code&gt;org.apache.commons.logging.LogFactory.HashtableImpl&lt;/code&gt;) </em>
<a name="160" href="#160">160</a> <em class="jxr_javadoccomment">     * value allows the &lt;code&gt;Hashtable&lt;/code&gt; used to store</em>
<a name="161" href="#161">161</a> <em class="jxr_javadoccomment">     * classloaders to be substituted by an alternative implementation.</em>
<a name="162" href="#162">162</a> <em class="jxr_javadoccomment">     * &lt;/p&gt;</em>
<a name="163" href="#163">163</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="164" href="#164">164</a> <em class="jxr_javadoccomment">     * &lt;strong&gt;Note:&lt;/strong&gt; &lt;code&gt;LogFactory&lt;/code&gt; will print:</em>
<a name="165" href="#165">165</a> <em class="jxr_javadoccomment">     * &lt;code&gt;&lt;pre&gt;</em>
<a name="166" href="#166">166</a> <em class="jxr_javadoccomment">     * [ERROR] LogFactory: Load of custom hashtable failed&lt;/em&gt;</em>
<a name="167" href="#167">167</a> <em class="jxr_javadoccomment">     * &lt;/pre&gt;&lt;/code&gt;</em>
<a name="168" href="#168">168</a> <em class="jxr_javadoccomment">     * to system error and then continue using a standard Hashtable.</em>
<a name="169" href="#169">169</a> <em class="jxr_javadoccomment">     * &lt;/p&gt;</em>
<a name="170" href="#170">170</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="171" href="#171">171</a> <em class="jxr_javadoccomment">     * &lt;strong&gt;Usage:&lt;/strong&gt; Set this property when Java is invoked</em>
<a name="172" href="#172">172</a> <em class="jxr_javadoccomment">     * and &lt;code&gt;LogFactory&lt;/code&gt; will attempt to load a new instance </em>
<a name="173" href="#173">173</a> <em class="jxr_javadoccomment">     * of the given implementation class.</em>
<a name="174" href="#174">174</a> <em class="jxr_javadoccomment">     * For example, running the following ant scriplet:</em>
<a name="175" href="#175">175</a> <em class="jxr_javadoccomment">     * &lt;code&gt;&lt;pre&gt;</em>
<a name="176" href="#176">176</a> <em class="jxr_javadoccomment">     *  &amp;lt;java classname="${test.runner}" fork="yes" failonerror="${test.failonerror}"&amp;gt;</em>
<a name="177" href="#177">177</a> <em class="jxr_javadoccomment">     *     ...</em>
<a name="178" href="#178">178</a> <em class="jxr_javadoccomment">     *     &amp;lt;sysproperty </em>
<a name="179" href="#179">179</a> <em class="jxr_javadoccomment">     *        key="org.apache.commons.logging.LogFactory.HashtableImpl"</em>
<a name="180" href="#180">180</a> <em class="jxr_javadoccomment">     *        value="org.apache.commons.logging.AltHashtable"/&amp;gt;</em>
<a name="181" href="#181">181</a> <em class="jxr_javadoccomment">     *  &amp;lt;/java&amp;gt;</em>
<a name="182" href="#182">182</a> <em class="jxr_javadoccomment">     * &lt;/pre&gt;&lt;/code&gt;</em>
<a name="183" href="#183">183</a> <em class="jxr_javadoccomment">     * will mean that &lt;code&gt;LogFactory&lt;/code&gt; will load an instance of</em>
<a name="184" href="#184">184</a> <em class="jxr_javadoccomment">     * &lt;code&gt;org.apache.commons.logging.AltHashtable&lt;/code&gt;.</em>
<a name="185" href="#185">185</a> <em class="jxr_javadoccomment">     * &lt;/p&gt;</em>
<a name="186" href="#186">186</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="187" href="#187">187</a> <em class="jxr_javadoccomment">     * A typical use case is to allow a custom</em>
<a name="188" href="#188">188</a> <em class="jxr_javadoccomment">     * Hashtable implementation using weak references to be substituted.</em>
<a name="189" href="#189">189</a> <em class="jxr_javadoccomment">     * This will allow classloaders to be garbage collected without</em>
<a name="190" href="#190">190</a> <em class="jxr_javadoccomment">     * the need to release them (on 1.3+ JVMs only, of course ;)</em>
<a name="191" href="#191">191</a> <em class="jxr_javadoccomment">     * &lt;/p&gt;</em>
<a name="192" href="#192">192</a> <em class="jxr_javadoccomment">     */</em>
<a name="193" href="#193">193</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> String HASHTABLE_IMPLEMENTATION_PROPERTY =
<a name="194" href="#194">194</a>         <span class="jxr_string">"org.apache.commons.logging.LogFactory.HashtableImpl"</span>;
<a name="195" href="#195">195</a>     <em class="jxr_javadoccomment">/**</em><em class="jxr_javadoccomment"> Name used to load the weak hashtable implementation by names */</em>
<a name="196" href="#196">196</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> String WEAK_HASHTABLE_CLASSNAME = 
<a name="197" href="#197">197</a>         <span class="jxr_string">"org.apache.commons.logging.impl.WeakHashtable"</span>;
<a name="198" href="#198">198</a> 
<a name="199" href="#199">199</a>     <em class="jxr_javadoccomment">/**</em>
<a name="200" href="#200">200</a> <em class="jxr_javadoccomment">     * A reference to the classloader that loaded this class. This is the</em>
<a name="201" href="#201">201</a> <em class="jxr_javadoccomment">     * same as LogFactory.class.getClassLoader(). However computing this</em>
<a name="202" href="#202">202</a> <em class="jxr_javadoccomment">     * value isn't quite as simple as that, as we potentially need to use</em>
<a name="203" href="#203">203</a> <em class="jxr_javadoccomment">     * AccessControllers etc. It's more efficient to compute it once and</em>
<a name="204" href="#204">204</a> <em class="jxr_javadoccomment">     * cache it here.</em>
<a name="205" href="#205">205</a> <em class="jxr_javadoccomment">     */</em>
<a name="206" href="#206">206</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> ClassLoader thisClassLoader;
<a name="207" href="#207">207</a>     
<a name="208" href="#208">208</a>     <em class="jxr_comment">// ----------------------------------------------------------- Constructors</em>
<a name="209" href="#209">209</a> 
<a name="210" href="#210">210</a> 
<a name="211" href="#211">211</a>     <em class="jxr_javadoccomment">/**</em>
<a name="212" href="#212">212</a> <em class="jxr_javadoccomment">     * Protected constructor that is not available for public use.</em>
<a name="213" href="#213">213</a> <em class="jxr_javadoccomment">     */</em>
<a name="214" href="#214">214</a>     <strong class="jxr_keyword">protected</strong> <a href="../../../../org/apache/commons/logging/LogFactory.html">LogFactory</a>() {
<a name="215" href="#215">215</a>     }
<a name="216" href="#216">216</a>     
<a name="217" href="#217">217</a>     <em class="jxr_comment">// --------------------------------------------------------- Public Methods</em>
<a name="218" href="#218">218</a> 
<a name="219" href="#219">219</a> 
<a name="220" href="#220">220</a>     <em class="jxr_javadoccomment">/**</em>
<a name="221" href="#221">221</a> <em class="jxr_javadoccomment">     * Return the configuration attribute with the specified name (if any),</em>
<a name="222" href="#222">222</a> <em class="jxr_javadoccomment">     * or &lt;code&gt;null&lt;/code&gt; if there is no such attribute.</em>
<a name="223" href="#223">223</a> <em class="jxr_javadoccomment">     *</em>
<a name="224" href="#224">224</a> <em class="jxr_javadoccomment">     * @param name Name of the attribute to return</em>
<a name="225" href="#225">225</a> <em class="jxr_javadoccomment">     */</em>
<a name="226" href="#226">226</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">abstract</strong> Object getAttribute(String name);
<a name="227" href="#227">227</a> 
<a name="228" href="#228">228</a> 
<a name="229" href="#229">229</a>     <em class="jxr_javadoccomment">/**</em>
<a name="230" href="#230">230</a> <em class="jxr_javadoccomment">     * Return an array containing the names of all currently defined</em>
<a name="231" href="#231">231</a> <em class="jxr_javadoccomment">     * configuration attributes.  If there are no such attributes, a zero</em>
<a name="232" href="#232">232</a> <em class="jxr_javadoccomment">     * length array is returned.</em>
<a name="233" href="#233">233</a> <em class="jxr_javadoccomment">     */</em>
<a name="234" href="#234">234</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">abstract</strong> String[] getAttributeNames();
<a name="235" href="#235">235</a> 
<a name="236" href="#236">236</a> 
<a name="237" href="#237">237</a>     <em class="jxr_javadoccomment">/**</em>
<a name="238" href="#238">238</a> <em class="jxr_javadoccomment">     * Convenience method to derive a name from the specified class and</em>
<a name="239" href="#239">239</a> <em class="jxr_javadoccomment">     * call &lt;code&gt;getInstance(String)&lt;/code&gt; with it.</em>
<a name="240" href="#240">240</a> <em class="jxr_javadoccomment">     *</em>
<a name="241" href="#241">241</a> <em class="jxr_javadoccomment">     * @param clazz Class for which a suitable Log name will be derived</em>
<a name="242" href="#242">242</a> <em class="jxr_javadoccomment">     *</em>
<a name="243" href="#243">243</a> <em class="jxr_javadoccomment">     * @exception LogConfigurationException if a suitable &lt;code&gt;Log&lt;/code&gt;</em>
<a name="244" href="#244">244</a> <em class="jxr_javadoccomment">     *  instance cannot be returned</em>
<a name="245" href="#245">245</a> <em class="jxr_javadoccomment">     */</em>
<a name="246" href="#246">246</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">abstract</strong> <a href="../../../../org/apache/commons/logging/Log.html">Log</a> getInstance(Class clazz)
<a name="247" href="#247">247</a>         <strong class="jxr_keyword">throws</strong> LogConfigurationException;
<a name="248" href="#248">248</a> 
<a name="249" href="#249">249</a> 
<a name="250" href="#250">250</a>     <em class="jxr_javadoccomment">/**</em>
<a name="251" href="#251">251</a> <em class="jxr_javadoccomment">     * &lt;p&gt;Construct (if necessary) and return a &lt;code&gt;Log&lt;/code&gt; instance,</em>
<a name="252" href="#252">252</a> <em class="jxr_javadoccomment">     * using the factory's current set of configuration attributes.&lt;/p&gt;</em>
<a name="253" href="#253">253</a> <em class="jxr_javadoccomment">     *</em>
<a name="254" href="#254">254</a> <em class="jxr_javadoccomment">     * &lt;p&gt;&lt;strong&gt;NOTE&lt;/strong&gt; - Depending upon the implementation of</em>
<a name="255" href="#255">255</a> <em class="jxr_javadoccomment">     * the &lt;code&gt;LogFactory&lt;/code&gt; you are using, the &lt;code&gt;Log&lt;/code&gt;</em>
<a name="256" href="#256">256</a> <em class="jxr_javadoccomment">     * instance you are returned may or may not be local to the current</em>
<a name="257" href="#257">257</a> <em class="jxr_javadoccomment">     * application, and may or may not be returned again on a subsequent</em>
<a name="258" href="#258">258</a> <em class="jxr_javadoccomment">     * call with the same name argument.&lt;/p&gt;</em>
<a name="259" href="#259">259</a> <em class="jxr_javadoccomment">     *</em>
<a name="260" href="#260">260</a> <em class="jxr_javadoccomment">     * @param name Logical name of the &lt;code&gt;Log&lt;/code&gt; instance to be</em>
<a name="261" href="#261">261</a> <em class="jxr_javadoccomment">     *  returned (the meaning of this name is only known to the underlying</em>
<a name="262" href="#262">262</a> <em class="jxr_javadoccomment">     *  logging implementation that is being wrapped)</em>
<a name="263" href="#263">263</a> <em class="jxr_javadoccomment">     *</em>
<a name="264" href="#264">264</a> <em class="jxr_javadoccomment">     * @exception LogConfigurationException if a suitable &lt;code&gt;Log&lt;/code&gt;</em>
<a name="265" href="#265">265</a> <em class="jxr_javadoccomment">     *  instance cannot be returned</em>
<a name="266" href="#266">266</a> <em class="jxr_javadoccomment">     */</em>
<a name="267" href="#267">267</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">abstract</strong> <a href="../../../../org/apache/commons/logging/Log.html">Log</a> getInstance(String name)
<a name="268" href="#268">268</a>         <strong class="jxr_keyword">throws</strong> LogConfigurationException;
<a name="269" href="#269">269</a> 
<a name="270" href="#270">270</a> 
<a name="271" href="#271">271</a>     <em class="jxr_javadoccomment">/**</em>
<a name="272" href="#272">272</a> <em class="jxr_javadoccomment">     * Release any internal references to previously created {@link Log}</em>
<a name="273" href="#273">273</a> <em class="jxr_javadoccomment">     * instances returned by this factory.  This is useful in environments</em>
<a name="274" href="#274">274</a> <em class="jxr_javadoccomment">     * like servlet containers, which implement application reloading by</em>
<a name="275" href="#275">275</a> <em class="jxr_javadoccomment">     * throwing away a ClassLoader.  Dangling references to objects in that</em>
<a name="276" href="#276">276</a> <em class="jxr_javadoccomment">     * class loader would prevent garbage collection.</em>
<a name="277" href="#277">277</a> <em class="jxr_javadoccomment">     */</em>
<a name="278" href="#278">278</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">abstract</strong> <strong class="jxr_keyword">void</strong> release();
<a name="279" href="#279">279</a> 
<a name="280" href="#280">280</a> 
<a name="281" href="#281">281</a>     <em class="jxr_javadoccomment">/**</em>
<a name="282" href="#282">282</a> <em class="jxr_javadoccomment">     * Remove any configuration attribute associated with the specified name.</em>
<a name="283" href="#283">283</a> <em class="jxr_javadoccomment">     * If there is no such attribute, no action is taken.</em>
<a name="284" href="#284">284</a> <em class="jxr_javadoccomment">     *</em>
<a name="285" href="#285">285</a> <em class="jxr_javadoccomment">     * @param name Name of the attribute to remove</em>
<a name="286" href="#286">286</a> <em class="jxr_javadoccomment">     */</em>
<a name="287" href="#287">287</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">abstract</strong> <strong class="jxr_keyword">void</strong> removeAttribute(String name);
<a name="288" href="#288">288</a> 
<a name="289" href="#289">289</a> 
<a name="290" href="#290">290</a>     <em class="jxr_javadoccomment">/**</em>
<a name="291" href="#291">291</a> <em class="jxr_javadoccomment">     * Set the configuration attribute with the specified name.  Calling</em>
<a name="292" href="#292">292</a> <em class="jxr_javadoccomment">     * this with a &lt;code&gt;null&lt;/code&gt; value is equivalent to calling</em>
<a name="293" href="#293">293</a> <em class="jxr_javadoccomment">     * &lt;code&gt;removeAttribute(name)&lt;/code&gt;.</em>
<a name="294" href="#294">294</a> <em class="jxr_javadoccomment">     *</em>
<a name="295" href="#295">295</a> <em class="jxr_javadoccomment">     * @param name Name of the attribute to set</em>
<a name="296" href="#296">296</a> <em class="jxr_javadoccomment">     * @param value Value of the attribute to set, or &lt;code&gt;null&lt;/code&gt;</em>
<a name="297" href="#297">297</a> <em class="jxr_javadoccomment">     *  to remove any setting for this attribute</em>
<a name="298" href="#298">298</a> <em class="jxr_javadoccomment">     */</em>
<a name="299" href="#299">299</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">abstract</strong> <strong class="jxr_keyword">void</strong> setAttribute(String name, Object value);
<a name="300" href="#300">300</a> 
<a name="301" href="#301">301</a> 
<a name="302" href="#302">302</a>     <em class="jxr_comment">// ------------------------------------------------------- Static Variables</em>
<a name="303" href="#303">303</a> 
<a name="304" href="#304">304</a> 
<a name="305" href="#305">305</a>     <em class="jxr_javadoccomment">/**</em>
<a name="306" href="#306">306</a> <em class="jxr_javadoccomment">     * The previously constructed &lt;code&gt;LogFactory&lt;/code&gt; instances, keyed by</em>
<a name="307" href="#307">307</a> <em class="jxr_javadoccomment">     * the &lt;code&gt;ClassLoader&lt;/code&gt; with which it was created.</em>
<a name="308" href="#308">308</a> <em class="jxr_javadoccomment">     */</em>
<a name="309" href="#309">309</a>     <strong class="jxr_keyword">protected</strong> <strong class="jxr_keyword">static</strong> Hashtable factories = <strong class="jxr_keyword">null</strong>;
<a name="310" href="#310">310</a>     
<a name="311" href="#311">311</a>     <em class="jxr_javadoccomment">/**</em>
<a name="312" href="#312">312</a> <em class="jxr_javadoccomment">     * Prevously constructed &lt;code&gt;LogFactory&lt;/code&gt; instance as in the</em>
<a name="313" href="#313">313</a> <em class="jxr_javadoccomment">     * &lt;code&gt;factories&lt;/code&gt; map, but for the case where</em>
<a name="314" href="#314">314</a> <em class="jxr_javadoccomment">     * &lt;code&gt;getClassLoader&lt;/code&gt; returns &lt;code&gt;null&lt;/code&gt;.</em>
<a name="315" href="#315">315</a> <em class="jxr_javadoccomment">     * This can happen when:</em>
<a name="316" href="#316">316</a> <em class="jxr_javadoccomment">     * &lt;ul&gt;</em>
<a name="317" href="#317">317</a> <em class="jxr_javadoccomment">     * &lt;li&gt;using JDK1.1 and the calling code is loaded via the system</em>
<a name="318" href="#318">318</a> <em class="jxr_javadoccomment">     *  classloader (very common)&lt;/li&gt;</em>
<a name="319" href="#319">319</a> <em class="jxr_javadoccomment">     * &lt;li&gt;using JDK1.2+ and the calling code is loaded via the boot</em>
<a name="320" href="#320">320</a> <em class="jxr_javadoccomment">     *  classloader (only likely for embedded systems work).&lt;/li&gt;</em>
<a name="321" href="#321">321</a> <em class="jxr_javadoccomment">     * &lt;/ul&gt;</em>
<a name="322" href="#322">322</a> <em class="jxr_javadoccomment">     * Note that &lt;code&gt;factories&lt;/code&gt; is a &lt;i&gt;Hashtable&lt;/i&gt; (not a HashMap),</em>
<a name="323" href="#323">323</a> <em class="jxr_javadoccomment">     * and hashtables don't allow null as a key.</em>
<a name="324" href="#324">324</a> <em class="jxr_javadoccomment">     */</em>
<a name="325" href="#325">325</a>     <strong class="jxr_keyword">protected</strong> <strong class="jxr_keyword">static</strong> <a href="../../../../org/apache/commons/logging/LogFactory.html">LogFactory</a> nullClassLoaderFactory = <strong class="jxr_keyword">null</strong>;
<a name="326" href="#326">326</a> 
<a name="327" href="#327">327</a>     <em class="jxr_javadoccomment">/**</em>
<a name="328" href="#328">328</a> <em class="jxr_javadoccomment">     * Create the hashtable which will be used to store a map of</em>
<a name="329" href="#329">329</a> <em class="jxr_javadoccomment">     * (context-classloader -&gt; logfactory-object). Version 1.2+ of Java</em>
<a name="330" href="#330">330</a> <em class="jxr_javadoccomment">     * supports "weak references", allowing a custom Hashtable class</em>
<a name="331" href="#331">331</a> <em class="jxr_javadoccomment">     * to be used which uses only weak references to its keys. Using weak</em>
<a name="332" href="#332">332</a> <em class="jxr_javadoccomment">     * references can fix memory leaks on webapp unload in some cases (though</em>
<a name="333" href="#333">333</a> <em class="jxr_javadoccomment">     * not all). Version 1.1 of Java does not support weak references, so we</em>
<a name="334" href="#334">334</a> <em class="jxr_javadoccomment">     * must dynamically determine which we are using. And just for fun, this</em>
<a name="335" href="#335">335</a> <em class="jxr_javadoccomment">     * code also supports the ability for a system property to specify an</em>
<a name="336" href="#336">336</a> <em class="jxr_javadoccomment">     * arbitrary Hashtable implementation name.</em>
<a name="337" href="#337">337</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="338" href="#338">338</a> <em class="jxr_javadoccomment">     * Note that the correct way to ensure no memory leaks occur is to ensure</em>
<a name="339" href="#339">339</a> <em class="jxr_javadoccomment">     * that LogFactory.release(contextClassLoader) is called whenever a </em>
<a name="340" href="#340">340</a> <em class="jxr_javadoccomment">     * webapp is undeployed.</em>
<a name="341" href="#341">341</a> <em class="jxr_javadoccomment">     */</em>
<a name="342" href="#342">342</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> Hashtable createFactoryStore() {
<a name="343" href="#343">343</a>         Hashtable result = <strong class="jxr_keyword">null</strong>;
<a name="344" href="#344">344</a>         String storeImplementationClass;
<a name="345" href="#345">345</a>         <strong class="jxr_keyword">try</strong> {
<a name="346" href="#346">346</a>             storeImplementationClass = getSystemProperty(HASHTABLE_IMPLEMENTATION_PROPERTY, <strong class="jxr_keyword">null</strong>);
<a name="347" href="#347">347</a>         } <strong class="jxr_keyword">catch</strong>(SecurityException ex) {
<a name="348" href="#348">348</a>             <em class="jxr_comment">// Permissions don't allow this to be accessed. Default to the "modern"</em>
<a name="349" href="#349">349</a>             <em class="jxr_comment">// weak hashtable implementation if it is available.</em>
<a name="350" href="#350">350</a>             storeImplementationClass = <strong class="jxr_keyword">null</strong>;
<a name="351" href="#351">351</a>         }
<a name="352" href="#352">352</a> 
<a name="353" href="#353">353</a>         <strong class="jxr_keyword">if</strong> (storeImplementationClass == <strong class="jxr_keyword">null</strong>) {
<a name="354" href="#354">354</a>             storeImplementationClass = WEAK_HASHTABLE_CLASSNAME;
<a name="355" href="#355">355</a>         }
<a name="356" href="#356">356</a>         <strong class="jxr_keyword">try</strong> {
<a name="357" href="#357">357</a>             Class implementationClass = Class.forName(storeImplementationClass);
<a name="358" href="#358">358</a>             result = (Hashtable) implementationClass.newInstance();
<a name="359" href="#359">359</a>             
<a name="360" href="#360">360</a>         } <strong class="jxr_keyword">catch</strong> (Throwable t) {
<a name="361" href="#361">361</a>             <em class="jxr_comment">// ignore</em>
<a name="362" href="#362">362</a>             <strong class="jxr_keyword">if</strong> (!WEAK_HASHTABLE_CLASSNAME.equals(storeImplementationClass)) {
<a name="363" href="#363">363</a>                 <em class="jxr_comment">// if the user's trying to set up a custom implementation, give a clue</em>
<a name="364" href="#364">364</a>                 <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="365" href="#365">365</a>                     <em class="jxr_comment">// use internal logging to issue the warning</em>
<a name="366" href="#366">366</a>                     logDiagnostic(<span class="jxr_string">"[ERROR] LogFactory: Load of custom hashtable failed"</span>);
<a name="367" href="#367">367</a>                 } <strong class="jxr_keyword">else</strong> {
<a name="368" href="#368">368</a>                     <em class="jxr_comment">// we *really* want this output, even if diagnostics weren't</em>
<a name="369" href="#369">369</a>                     <em class="jxr_comment">// explicitly enabled by the user.</em>
<a name="370" href="#370">370</a>                     System.err.println(<span class="jxr_string">"[ERROR] LogFactory: Load of custom hashtable failed"</span>);
<a name="371" href="#371">371</a>                 }
<a name="372" href="#372">372</a>             }
<a name="373" href="#373">373</a>         }
<a name="374" href="#374">374</a>         <strong class="jxr_keyword">if</strong> (result == <strong class="jxr_keyword">null</strong>) {
<a name="375" href="#375">375</a>             result = <strong class="jxr_keyword">new</strong> Hashtable();
<a name="376" href="#376">376</a>         }
<a name="377" href="#377">377</a>         <strong class="jxr_keyword">return</strong> result;
<a name="378" href="#378">378</a>     }
<a name="379" href="#379">379</a> 
<a name="380" href="#380">380</a> 
<a name="381" href="#381">381</a>     <em class="jxr_comment">// --------------------------------------------------------- Static Methods</em>
<a name="382" href="#382">382</a> 
<a name="383" href="#383">383</a>     <em class="jxr_javadoccomment">/**</em><em class="jxr_javadoccomment"> Utility method to safely trim a string. */</em>
<a name="384" href="#384">384</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> String trim(String src) {
<a name="385" href="#385">385</a>     	<strong class="jxr_keyword">if</strong> (src == <strong class="jxr_keyword">null</strong>) {
<a name="386" href="#386">386</a>     		<strong class="jxr_keyword">return</strong> <strong class="jxr_keyword">null</strong>;
<a name="387" href="#387">387</a>     	}
<a name="388" href="#388">388</a>     	<strong class="jxr_keyword">return</strong> src.trim();
<a name="389" href="#389">389</a>     }
<a name="390" href="#390">390</a> 
<a name="391" href="#391">391</a>     <em class="jxr_javadoccomment">/**</em>
<a name="392" href="#392">392</a> <em class="jxr_javadoccomment">     * &lt;p&gt;Construct (if necessary) and return a &lt;code&gt;LogFactory&lt;/code&gt;</em>
<a name="393" href="#393">393</a> <em class="jxr_javadoccomment">     * instance, using the following ordered lookup procedure to determine</em>
<a name="394" href="#394">394</a> <em class="jxr_javadoccomment">     * the name of the implementation class to be loaded.&lt;/p&gt;</em>
<a name="395" href="#395">395</a> <em class="jxr_javadoccomment">     * &lt;ul&gt;</em>
<a name="396" href="#396">396</a> <em class="jxr_javadoccomment">     * &lt;li&gt;The &lt;code&gt;org.apache.commons.logging.LogFactory&lt;/code&gt; system</em>
<a name="397" href="#397">397</a> <em class="jxr_javadoccomment">     *     property.&lt;/li&gt;</em>
<a name="398" href="#398">398</a> <em class="jxr_javadoccomment">     * &lt;li&gt;The JDK 1.3 Service Discovery mechanism&lt;/li&gt;</em>
<a name="399" href="#399">399</a> <em class="jxr_javadoccomment">     * &lt;li&gt;Use the properties file &lt;code&gt;commons-logging.properties&lt;/code&gt;</em>
<a name="400" href="#400">400</a> <em class="jxr_javadoccomment">     *     file, if found in the class path of this class.  The configuration</em>
<a name="401" href="#401">401</a> <em class="jxr_javadoccomment">     *     file is in standard &lt;code&gt;java.util.Properties&lt;/code&gt; format and</em>
<a name="402" href="#402">402</a> <em class="jxr_javadoccomment">     *     contains the fully qualified name of the implementation class</em>
<a name="403" href="#403">403</a> <em class="jxr_javadoccomment">     *     with the key being the system property defined above.&lt;/li&gt;</em>
<a name="404" href="#404">404</a> <em class="jxr_javadoccomment">     * &lt;li&gt;Fall back to a default implementation class</em>
<a name="405" href="#405">405</a> <em class="jxr_javadoccomment">     *     (&lt;code&gt;org.apache.commons.logging.impl.LogFactoryImpl&lt;/code&gt;).&lt;/li&gt;</em>
<a name="406" href="#406">406</a> <em class="jxr_javadoccomment">     * &lt;/ul&gt;</em>
<a name="407" href="#407">407</a> <em class="jxr_javadoccomment">     *</em>
<a name="408" href="#408">408</a> <em class="jxr_javadoccomment">     * &lt;p&gt;&lt;em&gt;NOTE&lt;/em&gt; - If the properties file method of identifying the</em>
<a name="409" href="#409">409</a> <em class="jxr_javadoccomment">     * &lt;code&gt;LogFactory&lt;/code&gt; implementation class is utilized, all of the</em>
<a name="410" href="#410">410</a> <em class="jxr_javadoccomment">     * properties defined in this file will be set as configuration attributes</em>
<a name="411" href="#411">411</a> <em class="jxr_javadoccomment">     * on the corresponding &lt;code&gt;LogFactory&lt;/code&gt; instance.&lt;/p&gt;</em>
<a name="412" href="#412">412</a> <em class="jxr_javadoccomment">     * </em>
<a name="413" href="#413">413</a> <em class="jxr_javadoccomment">     * &lt;p&gt;&lt;em&gt;NOTE&lt;/em&gt; - In a multithreaded environment it is possible </em>
<a name="414" href="#414">414</a> <em class="jxr_javadoccomment">     * that two different instances will be returned for the same </em>
<a name="415" href="#415">415</a> <em class="jxr_javadoccomment">     * classloader environment. </em>
<a name="416" href="#416">416</a> <em class="jxr_javadoccomment">     * &lt;/p&gt;</em>
<a name="417" href="#417">417</a> <em class="jxr_javadoccomment">     *</em>
<a name="418" href="#418">418</a> <em class="jxr_javadoccomment">     * @exception LogConfigurationException if the implementation class is not</em>
<a name="419" href="#419">419</a> <em class="jxr_javadoccomment">     *  available or cannot be instantiated.</em>
<a name="420" href="#420">420</a> <em class="jxr_javadoccomment">     */</em>
<a name="421" href="#421">421</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <a href="../../../../org/apache/commons/logging/LogFactory.html">LogFactory</a> getFactory() <strong class="jxr_keyword">throws</strong> LogConfigurationException {
<a name="422" href="#422">422</a>         <em class="jxr_comment">// Identify the class loader we will be using</em>
<a name="423" href="#423">423</a>         ClassLoader contextClassLoader = getContextClassLoaderInternal();
<a name="424" href="#424">424</a> 
<a name="425" href="#425">425</a>         <strong class="jxr_keyword">if</strong> (contextClassLoader == <strong class="jxr_keyword">null</strong>) {
<a name="426" href="#426">426</a>             <em class="jxr_comment">// This is an odd enough situation to report about. This</em>
<a name="427" href="#427">427</a>             <em class="jxr_comment">// output will be a nuisance on JDK1.1, as the system</em>
<a name="428" href="#428">428</a>             <em class="jxr_comment">// classloader is null in that environment.</em>
<a name="429" href="#429">429</a>             <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="430" href="#430">430</a>                 logDiagnostic(<span class="jxr_string">"Context classloader is null."</span>);
<a name="431" href="#431">431</a>             }
<a name="432" href="#432">432</a>         }
<a name="433" href="#433">433</a> 
<a name="434" href="#434">434</a>         <em class="jxr_comment">// Return any previously registered factory for this class loader</em>
<a name="435" href="#435">435</a>         <a href="../../../../org/apache/commons/logging/LogFactory.html">LogFactory</a> factory = getCachedFactory(contextClassLoader);
<a name="436" href="#436">436</a>         <strong class="jxr_keyword">if</strong> (factory != <strong class="jxr_keyword">null</strong>) {
<a name="437" href="#437">437</a>             <strong class="jxr_keyword">return</strong> factory;
<a name="438" href="#438">438</a>         }
<a name="439" href="#439">439</a> 
<a name="440" href="#440">440</a>         <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="441" href="#441">441</a>             logDiagnostic(
<a name="442" href="#442">442</a>                     <span class="jxr_string">"[LOOKUP] LogFactory implementation requested for the first time for context classloader "</span>
<a name="443" href="#443">443</a>                     + objectId(contextClassLoader));
<a name="444" href="#444">444</a>             logHierarchy(<span class="jxr_string">"[LOOKUP] "</span>, contextClassLoader);
<a name="445" href="#445">445</a>         }
<a name="446" href="#446">446</a> 
<a name="447" href="#447">447</a>         <em class="jxr_comment">// Load properties file.</em>
<a name="448" href="#448">448</a>         <em class="jxr_comment">//</em>
<a name="449" href="#449">449</a>         <em class="jxr_comment">// If the properties file exists, then its contents are used as</em>
<a name="450" href="#450">450</a>         <em class="jxr_comment">// "attributes" on the LogFactory implementation class. One particular</em>
<a name="451" href="#451">451</a>         <em class="jxr_comment">// property may also control which LogFactory concrete subclass is</em>
<a name="452" href="#452">452</a>         <em class="jxr_comment">// used, but only if other discovery mechanisms fail..</em>
<a name="453" href="#453">453</a>         <em class="jxr_comment">//</em>
<a name="454" href="#454">454</a>         <em class="jxr_comment">// As the properties file (if it exists) will be used one way or </em>
<a name="455" href="#455">455</a>         <em class="jxr_comment">// another in the end we may as well look for it first.</em>
<a name="456" href="#456">456</a> 
<a name="457" href="#457">457</a>         Properties props = getConfigurationFile(contextClassLoader, FACTORY_PROPERTIES);
<a name="458" href="#458">458</a> 
<a name="459" href="#459">459</a>         <em class="jxr_comment">// Determine whether we will be using the thread context class loader to</em>
<a name="460" href="#460">460</a>         <em class="jxr_comment">// load logging classes or not by checking the loaded properties file (if any).</em>
<a name="461" href="#461">461</a>         ClassLoader baseClassLoader = contextClassLoader;
<a name="462" href="#462">462</a>         <strong class="jxr_keyword">if</strong> (props != <strong class="jxr_keyword">null</strong>) {
<a name="463" href="#463">463</a>             String useTCCLStr = props.getProperty(TCCL_KEY);
<a name="464" href="#464">464</a>             <strong class="jxr_keyword">if</strong> (useTCCLStr != <strong class="jxr_keyword">null</strong>) {
<a name="465" href="#465">465</a>                 <em class="jxr_comment">// The Boolean.valueOf(useTCCLStr).booleanValue() formulation</em>
<a name="466" href="#466">466</a>                 <em class="jxr_comment">// is required for Java 1.2 compatability.</em>
<a name="467" href="#467">467</a>                 <strong class="jxr_keyword">if</strong> (Boolean.valueOf(useTCCLStr).booleanValue() == false) {
<a name="468" href="#468">468</a>                     <em class="jxr_comment">// Don't use current context classloader when locating any</em>
<a name="469" href="#469">469</a>                     <em class="jxr_comment">// LogFactory or Log classes, just use the class that loaded</em>
<a name="470" href="#470">470</a>                     <em class="jxr_comment">// this abstract class. When this class is deployed in a shared</em>
<a name="471" href="#471">471</a>                     <em class="jxr_comment">// classpath of a container, it means webapps cannot deploy their</em>
<a name="472" href="#472">472</a>                     <em class="jxr_comment">// own logging implementations. It also means that it is up to the</em>
<a name="473" href="#473">473</a>                     <em class="jxr_comment">// implementation whether to load library-specific config files</em>
<a name="474" href="#474">474</a>                     <em class="jxr_comment">// from the TCCL or not.</em>
<a name="475" href="#475">475</a>                     baseClassLoader = thisClassLoader; 
<a name="476" href="#476">476</a>                 }
<a name="477" href="#477">477</a>             }
<a name="478" href="#478">478</a>         }
<a name="479" href="#479">479</a> 
<a name="480" href="#480">480</a>         <em class="jxr_comment">// Determine which concrete LogFactory subclass to use.</em>
<a name="481" href="#481">481</a>         <em class="jxr_comment">// First, try a global system property</em>
<a name="482" href="#482">482</a>         <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="483" href="#483">483</a>             logDiagnostic(
<a name="484" href="#484">484</a>                     <span class="jxr_string">"[LOOKUP] Looking for system property ["</span> + FACTORY_PROPERTY 
<a name="485" href="#485">485</a>                     + <span class="jxr_string">"] to define the LogFactory subclass to use..."</span>);
<a name="486" href="#486">486</a>         }
<a name="487" href="#487">487</a>         
<a name="488" href="#488">488</a>         <strong class="jxr_keyword">try</strong> {
<a name="489" href="#489">489</a>             String factoryClass = getSystemProperty(FACTORY_PROPERTY, <strong class="jxr_keyword">null</strong>);
<a name="490" href="#490">490</a>             <strong class="jxr_keyword">if</strong> (factoryClass != <strong class="jxr_keyword">null</strong>) {
<a name="491" href="#491">491</a>                 <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="492" href="#492">492</a>                     logDiagnostic(
<a name="493" href="#493">493</a>                             <span class="jxr_string">"[LOOKUP] Creating an instance of LogFactory class '"</span> + factoryClass
<a name="494" href="#494">494</a>                             + <span class="jxr_string">"' as specified by system property "</span> + FACTORY_PROPERTY);
<a name="495" href="#495">495</a>                 }
<a name="496" href="#496">496</a>                 
<a name="497" href="#497">497</a>                 factory = newFactory(factoryClass, baseClassLoader, contextClassLoader);
<a name="498" href="#498">498</a>             } <strong class="jxr_keyword">else</strong> {
<a name="499" href="#499">499</a>                 <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="500" href="#500">500</a>                     logDiagnostic(
<a name="501" href="#501">501</a>                             <span class="jxr_string">"[LOOKUP] No system property ["</span> + FACTORY_PROPERTY 
<a name="502" href="#502">502</a>                             + <span class="jxr_string">"] defined."</span>);
<a name="503" href="#503">503</a>                 }
<a name="504" href="#504">504</a>             }
<a name="505" href="#505">505</a>         } <strong class="jxr_keyword">catch</strong> (SecurityException e) {
<a name="506" href="#506">506</a>             <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="507" href="#507">507</a>                 logDiagnostic(
<a name="508" href="#508">508</a>                         <span class="jxr_string">"[LOOKUP] A security exception occurred while trying to create an"</span>
<a name="509" href="#509">509</a>                         + <span class="jxr_string">" instance of the custom factory class"</span>
<a name="510" href="#510">510</a>                         + <span class="jxr_string">": ["</span> + trim(e.getMessage())
<a name="511" href="#511">511</a>                         + <span class="jxr_string">"]. Trying alternative implementations..."</span>);
<a name="512" href="#512">512</a>             }
<a name="513" href="#513">513</a>             ;  <em class="jxr_comment">// ignore</em>
<a name="514" href="#514">514</a>         } <strong class="jxr_keyword">catch</strong>(RuntimeException e) {
<a name="515" href="#515">515</a>             <em class="jxr_comment">// This is not consistent with the behaviour when a bad LogFactory class is</em>
<a name="516" href="#516">516</a>             <em class="jxr_comment">// specified in a services file.</em>
<a name="517" href="#517">517</a>             <em class="jxr_comment">//</em>
<a name="518" href="#518">518</a>             <em class="jxr_comment">// One possible exception that can occur here is a ClassCastException when</em>
<a name="519" href="#519">519</a>             <em class="jxr_comment">// the specified class wasn't castable to this LogFactory type.</em>
<a name="520" href="#520">520</a>             <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="521" href="#521">521</a>                 logDiagnostic(
<a name="522" href="#522">522</a>                         <span class="jxr_string">"[LOOKUP] An exception occurred while trying to create an"</span>
<a name="523" href="#523">523</a>                         + <span class="jxr_string">" instance of the custom factory class"</span>
<a name="524" href="#524">524</a>                         + <span class="jxr_string">": ["</span> + trim(e.getMessage())
<a name="525" href="#525">525</a>                         + <span class="jxr_string">"] as specified by a system property."</span>);
<a name="526" href="#526">526</a>             }
<a name="527" href="#527">527</a>             <strong class="jxr_keyword">throw</strong> e;
<a name="528" href="#528">528</a>         }
<a name="529" href="#529">529</a> 
<a name="530" href="#530">530</a> 
<a name="531" href="#531">531</a>         <em class="jxr_comment">// Second, try to find a service by using the JDK1.3 class</em>
<a name="532" href="#532">532</a>         <em class="jxr_comment">// discovery mechanism, which involves putting a file with the name</em>
<a name="533" href="#533">533</a>         <em class="jxr_comment">// of an interface class in the META-INF/services directory, where the</em>
<a name="534" href="#534">534</a>         <em class="jxr_comment">// contents of the file is a single line specifying a concrete class </em>
<a name="535" href="#535">535</a>         <em class="jxr_comment">// that implements the desired interface.</em>
<a name="536" href="#536">536</a> 
<a name="537" href="#537">537</a>         <strong class="jxr_keyword">if</strong> (factory == <strong class="jxr_keyword">null</strong>) {
<a name="538" href="#538">538</a>             <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="539" href="#539">539</a>                 logDiagnostic(
<a name="540" href="#540">540</a>                         <span class="jxr_string">"[LOOKUP] Looking for a resource file of name ["</span> + SERVICE_ID
<a name="541" href="#541">541</a>                         + <span class="jxr_string">"] to define the LogFactory subclass to use..."</span>);
<a name="542" href="#542">542</a>             }
<a name="543" href="#543">543</a>             <strong class="jxr_keyword">try</strong> {
<a name="544" href="#544">544</a>                 InputStream is = getResourceAsStream(contextClassLoader,
<a name="545" href="#545">545</a>                                                      SERVICE_ID);
<a name="546" href="#546">546</a> 
<a name="547" href="#547">547</a>                 <strong class="jxr_keyword">if</strong>( is != <strong class="jxr_keyword">null</strong> ) {
<a name="548" href="#548">548</a>                     <em class="jxr_comment">// This code is needed by EBCDIC and other strange systems.</em>
<a name="549" href="#549">549</a>                     <em class="jxr_comment">// It's a fix for bugs reported in xerces</em>
<a name="550" href="#550">550</a>                     BufferedReader rd;
<a name="551" href="#551">551</a>                     <strong class="jxr_keyword">try</strong> {
<a name="552" href="#552">552</a>                         rd = <strong class="jxr_keyword">new</strong> BufferedReader(<strong class="jxr_keyword">new</strong> InputStreamReader(is, <span class="jxr_string">"UTF-8"</span>));
<a name="553" href="#553">553</a>                     } <strong class="jxr_keyword">catch</strong> (java.io.UnsupportedEncodingException e) {
<a name="554" href="#554">554</a>                         rd = <strong class="jxr_keyword">new</strong> BufferedReader(<strong class="jxr_keyword">new</strong> InputStreamReader(is));
<a name="555" href="#555">555</a>                     }
<a name="556" href="#556">556</a> 
<a name="557" href="#557">557</a>                     String factoryClassName = rd.readLine();
<a name="558" href="#558">558</a>                     rd.close();
<a name="559" href="#559">559</a> 
<a name="560" href="#560">560</a>                     <strong class="jxr_keyword">if</strong> (factoryClassName != <strong class="jxr_keyword">null</strong> &amp;&amp;
<a name="561" href="#561">561</a>                         ! <span class="jxr_string">""</span>.equals(factoryClassName)) {
<a name="562" href="#562">562</a>                         <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="563" href="#563">563</a>                             logDiagnostic(
<a name="564" href="#564">564</a>                                     <span class="jxr_string">"[LOOKUP]  Creating an instance of LogFactory class "</span> + factoryClassName
<a name="565" href="#565">565</a>                                     + <span class="jxr_string">" as specified by file '"</span> + SERVICE_ID 
<a name="566" href="#566">566</a>                                     + <span class="jxr_string">"' which was present in the path of the context"</span>
<a name="567" href="#567">567</a>                                     + <span class="jxr_string">" classloader."</span>);
<a name="568" href="#568">568</a>                         }
<a name="569" href="#569">569</a>                         factory = newFactory(factoryClassName, baseClassLoader, contextClassLoader );
<a name="570" href="#570">570</a>                     }
<a name="571" href="#571">571</a>                 } <strong class="jxr_keyword">else</strong> {
<a name="572" href="#572">572</a>                     <em class="jxr_comment">// is == null</em>
<a name="573" href="#573">573</a>                     <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="574" href="#574">574</a>                         logDiagnostic(
<a name="575" href="#575">575</a>                             <span class="jxr_string">"[LOOKUP] No resource file with name '"</span> + SERVICE_ID
<a name="576" href="#576">576</a>                             + <span class="jxr_string">"' found."</span>);
<a name="577" href="#577">577</a>                     }
<a name="578" href="#578">578</a>                 }
<a name="579" href="#579">579</a>             } <strong class="jxr_keyword">catch</strong>( Exception ex ) {
<a name="580" href="#580">580</a>                 <em class="jxr_comment">// note: if the specified LogFactory class wasn't compatible with LogFactory</em>
<a name="581" href="#581">581</a>                 <em class="jxr_comment">// for some reason, a ClassCastException will be caught here, and attempts will</em>
<a name="582" href="#582">582</a>                 <em class="jxr_comment">// continue to find a compatible class.</em>
<a name="583" href="#583">583</a>                 <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="584" href="#584">584</a>                     logDiagnostic(
<a name="585" href="#585">585</a>                         <span class="jxr_string">"[LOOKUP] A security exception occurred while trying to create an"</span>
<a name="586" href="#586">586</a>                         + <span class="jxr_string">" instance of the custom factory class"</span>
<a name="587" href="#587">587</a>                         + <span class="jxr_string">": ["</span> + trim(ex.getMessage())
<a name="588" href="#588">588</a>                         + <span class="jxr_string">"]. Trying alternative implementations..."</span>);
<a name="589" href="#589">589</a>                 }
<a name="590" href="#590">590</a>                 ; <em class="jxr_comment">// ignore</em>
<a name="591" href="#591">591</a>             }
<a name="592" href="#592">592</a>         }
<a name="593" href="#593">593</a> 
<a name="594" href="#594">594</a> 
<a name="595" href="#595">595</a>         <em class="jxr_comment">// Third try looking into the properties file read earlier (if found)</em>
<a name="596" href="#596">596</a> 
<a name="597" href="#597">597</a>         <strong class="jxr_keyword">if</strong> (factory == <strong class="jxr_keyword">null</strong>) {
<a name="598" href="#598">598</a>             <strong class="jxr_keyword">if</strong> (props != <strong class="jxr_keyword">null</strong>) {
<a name="599" href="#599">599</a>                 <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="600" href="#600">600</a>                     logDiagnostic(
<a name="601" href="#601">601</a>                         <span class="jxr_string">"[LOOKUP] Looking in properties file for entry with key '"</span> 
<a name="602" href="#602">602</a>                         + FACTORY_PROPERTY
<a name="603" href="#603">603</a>                         + <span class="jxr_string">"' to define the LogFactory subclass to use..."</span>);
<a name="604" href="#604">604</a>                 }
<a name="605" href="#605">605</a>                 String factoryClass = props.getProperty(FACTORY_PROPERTY);
<a name="606" href="#606">606</a>                 <strong class="jxr_keyword">if</strong> (factoryClass != <strong class="jxr_keyword">null</strong>) {
<a name="607" href="#607">607</a>                     <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="608" href="#608">608</a>                         logDiagnostic(
<a name="609" href="#609">609</a>                             <span class="jxr_string">"[LOOKUP] Properties file specifies LogFactory subclass '"</span> 
<a name="610" href="#610">610</a>                             + factoryClass + <span class="jxr_string">"'"</span>);
<a name="611" href="#611">611</a>                     }
<a name="612" href="#612">612</a>                     factory = newFactory(factoryClass, baseClassLoader, contextClassLoader);
<a name="613" href="#613">613</a>                     
<a name="614" href="#614">614</a>                     <em class="jxr_comment">// TODO: think about whether we need to handle exceptions from newFactory</em>
<a name="615" href="#615">615</a>                 } <strong class="jxr_keyword">else</strong> {
<a name="616" href="#616">616</a>                     <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="617" href="#617">617</a>                         logDiagnostic(
<a name="618" href="#618">618</a>                             <span class="jxr_string">"[LOOKUP] Properties file has no entry specifying LogFactory subclass."</span>);
<a name="619" href="#619">619</a>                     }
<a name="620" href="#620">620</a>                 }
<a name="621" href="#621">621</a>             } <strong class="jxr_keyword">else</strong> {
<a name="622" href="#622">622</a>                 <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="623" href="#623">623</a>                     logDiagnostic(
<a name="624" href="#624">624</a>                         <span class="jxr_string">"[LOOKUP] No properties file available to determine"</span>
<a name="625" href="#625">625</a>                         + <span class="jxr_string">" LogFactory subclass from.."</span>);
<a name="626" href="#626">626</a>                 }
<a name="627" href="#627">627</a>             }
<a name="628" href="#628">628</a>         }
<a name="629" href="#629">629</a> 
<a name="630" href="#630">630</a> 
<a name="631" href="#631">631</a>         <em class="jxr_comment">// Fourth, try the fallback implementation class</em>
<a name="632" href="#632">632</a> 
<a name="633" href="#633">633</a>         <strong class="jxr_keyword">if</strong> (factory == <strong class="jxr_keyword">null</strong>) {
<a name="634" href="#634">634</a>             <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="635" href="#635">635</a>                 logDiagnostic(
<a name="636" href="#636">636</a>                 <span class="jxr_string">"[LOOKUP] Loading the default LogFactory implementation '"</span> + FACTORY_DEFAULT
<a name="637" href="#637">637</a>                 + <span class="jxr_string">"' via the same classloader that loaded this LogFactory"</span>
<a name="638" href="#638">638</a>                 + <span class="jxr_string">" class (ie not looking in the context classloader)."</span>);
<a name="639" href="#639">639</a>             }
<a name="640" href="#640">640</a>             
<a name="641" href="#641">641</a>             <em class="jxr_comment">// Note: unlike the above code which can try to load custom LogFactory</em>
<a name="642" href="#642">642</a>             <em class="jxr_comment">// implementations via the TCCL, we don't try to load the default LogFactory</em>
<a name="643" href="#643">643</a>             <em class="jxr_comment">// implementation via the context classloader because:</em>
<a name="644" href="#644">644</a>             <em class="jxr_comment">// * that can cause problems (see comments in newFactory method)</em>
<a name="645" href="#645">645</a>             <em class="jxr_comment">// * no-one should be customising the code of the default class</em>
<a name="646" href="#646">646</a>             <em class="jxr_comment">// Yes, we do give up the ability for the child to ship a newer</em>
<a name="647" href="#647">647</a>             <em class="jxr_comment">// version of the LogFactoryImpl class and have it used dynamically</em>
<a name="648" href="#648">648</a>             <em class="jxr_comment">// by an old LogFactory class in the parent, but that isn't </em>
<a name="649" href="#649">649</a>             <em class="jxr_comment">// necessarily a good idea anyway.</em>
<a name="650" href="#650">650</a>             factory = newFactory(FACTORY_DEFAULT, thisClassLoader, contextClassLoader);
<a name="651" href="#651">651</a>         }
<a name="652" href="#652">652</a> 
<a name="653" href="#653">653</a>         <strong class="jxr_keyword">if</strong> (factory != <strong class="jxr_keyword">null</strong>) {
<a name="654" href="#654">654</a>             <em class="jxr_javadoccomment">/**</em>
<a name="655" href="#655">655</a> <em class="jxr_javadoccomment">             * Always cache using context class loader.</em>
<a name="656" href="#656">656</a> <em class="jxr_javadoccomment">             */</em>
<a name="657" href="#657">657</a>             cacheFactory(contextClassLoader, factory);
<a name="658" href="#658">658</a> 
<a name="659" href="#659">659</a>             <strong class="jxr_keyword">if</strong>( props!=<strong class="jxr_keyword">null</strong> ) {
<a name="660" href="#660">660</a>                 Enumeration names = props.propertyNames();
<a name="661" href="#661">661</a>                 <strong class="jxr_keyword">while</strong> (names.hasMoreElements()) {
<a name="662" href="#662">662</a>                     String name = (String) names.nextElement();
<a name="663" href="#663">663</a>                     String value = props.getProperty(name);
<a name="664" href="#664">664</a>                     factory.setAttribute(name, value);
<a name="665" href="#665">665</a>                 }
<a name="666" href="#666">666</a>             }
<a name="667" href="#667">667</a>         }
<a name="668" href="#668">668</a> 
<a name="669" href="#669">669</a>         <strong class="jxr_keyword">return</strong> factory;
<a name="670" href="#670">670</a>     }
<a name="671" href="#671">671</a> 
<a name="672" href="#672">672</a> 
<a name="673" href="#673">673</a>     <em class="jxr_javadoccomment">/**</em>
<a name="674" href="#674">674</a> <em class="jxr_javadoccomment">     * Convenience method to return a named logger, without the application</em>
<a name="675" href="#675">675</a> <em class="jxr_javadoccomment">     * having to care about factories.</em>
<a name="676" href="#676">676</a> <em class="jxr_javadoccomment">     *</em>
<a name="677" href="#677">677</a> <em class="jxr_javadoccomment">     * @param clazz Class from which a log name will be derived</em>
<a name="678" href="#678">678</a> <em class="jxr_javadoccomment">     *</em>
<a name="679" href="#679">679</a> <em class="jxr_javadoccomment">     * @exception LogConfigurationException if a suitable &lt;code&gt;Log&lt;/code&gt;</em>
<a name="680" href="#680">680</a> <em class="jxr_javadoccomment">     *  instance cannot be returned</em>
<a name="681" href="#681">681</a> <em class="jxr_javadoccomment">     */</em>
<a name="682" href="#682">682</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <a href="../../../../org/apache/commons/logging/Log.html">Log</a> getLog(Class clazz)
<a name="683" href="#683">683</a>         <strong class="jxr_keyword">throws</strong> <a href="../../../../org/apache/commons/logging/LogConfigurationException.html">LogConfigurationException</a> {
<a name="684" href="#684">684</a> 
<a name="685" href="#685">685</a>         <strong class="jxr_keyword">return</strong> (getFactory().getInstance(clazz));
<a name="686" href="#686">686</a> 
<a name="687" href="#687">687</a>     }
<a name="688" href="#688">688</a> 
<a name="689" href="#689">689</a> 
<a name="690" href="#690">690</a>     <em class="jxr_javadoccomment">/**</em>
<a name="691" href="#691">691</a> <em class="jxr_javadoccomment">     * Convenience method to return a named logger, without the application</em>
<a name="692" href="#692">692</a> <em class="jxr_javadoccomment">     * having to care about factories.</em>
<a name="693" href="#693">693</a> <em class="jxr_javadoccomment">     *</em>
<a name="694" href="#694">694</a> <em class="jxr_javadoccomment">     * @param name Logical name of the &lt;code&gt;Log&lt;/code&gt; instance to be</em>
<a name="695" href="#695">695</a> <em class="jxr_javadoccomment">     *  returned (the meaning of this name is only known to the underlying</em>
<a name="696" href="#696">696</a> <em class="jxr_javadoccomment">     *  logging implementation that is being wrapped)</em>
<a name="697" href="#697">697</a> <em class="jxr_javadoccomment">     *</em>
<a name="698" href="#698">698</a> <em class="jxr_javadoccomment">     * @exception LogConfigurationException if a suitable &lt;code&gt;Log&lt;/code&gt;</em>
<a name="699" href="#699">699</a> <em class="jxr_javadoccomment">     *  instance cannot be returned</em>
<a name="700" href="#700">700</a> <em class="jxr_javadoccomment">     */</em>
<a name="701" href="#701">701</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <a href="../../../../org/apache/commons/logging/Log.html">Log</a> getLog(String name)
<a name="702" href="#702">702</a>         <strong class="jxr_keyword">throws</strong> <a href="../../../../org/apache/commons/logging/LogConfigurationException.html">LogConfigurationException</a> {
<a name="703" href="#703">703</a> 
<a name="704" href="#704">704</a>         <strong class="jxr_keyword">return</strong> (getFactory().getInstance(name));
<a name="705" href="#705">705</a> 
<a name="706" href="#706">706</a>     }
<a name="707" href="#707">707</a> 
<a name="708" href="#708">708</a> 
<a name="709" href="#709">709</a>     <em class="jxr_javadoccomment">/**</em>
<a name="710" href="#710">710</a> <em class="jxr_javadoccomment">     * Release any internal references to previously created {@link LogFactory}</em>
<a name="711" href="#711">711</a> <em class="jxr_javadoccomment">     * instances that have been associated with the specified class loader</em>
<a name="712" href="#712">712</a> <em class="jxr_javadoccomment">     * (if any), after calling the instance method &lt;code&gt;release()&lt;/code&gt; on</em>
<a name="713" href="#713">713</a> <em class="jxr_javadoccomment">     * each of them.</em>
<a name="714" href="#714">714</a> <em class="jxr_javadoccomment">     *</em>
<a name="715" href="#715">715</a> <em class="jxr_javadoccomment">     * @param classLoader ClassLoader for which to release the LogFactory</em>
<a name="716" href="#716">716</a> <em class="jxr_javadoccomment">     */</em>
<a name="717" href="#717">717</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">void</strong> release(ClassLoader classLoader) {
<a name="718" href="#718">718</a> 
<a name="719" href="#719">719</a>         <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="720" href="#720">720</a>             logDiagnostic(<span class="jxr_string">"Releasing factory for classloader "</span> + objectId(classLoader));
<a name="721" href="#721">721</a>         }
<a name="722" href="#722">722</a>         <strong class="jxr_keyword">synchronized</strong> (factories) {
<a name="723" href="#723">723</a>             <strong class="jxr_keyword">if</strong> (classLoader == <strong class="jxr_keyword">null</strong>) {
<a name="724" href="#724">724</a>                 <strong class="jxr_keyword">if</strong> (nullClassLoaderFactory != <strong class="jxr_keyword">null</strong>) {
<a name="725" href="#725">725</a>                     nullClassLoaderFactory.release();
<a name="726" href="#726">726</a>                     nullClassLoaderFactory = <strong class="jxr_keyword">null</strong>;
<a name="727" href="#727">727</a>                 }
<a name="728" href="#728">728</a>             } <strong class="jxr_keyword">else</strong> {
<a name="729" href="#729">729</a>                 <a href="../../../../org/apache/commons/logging/LogFactory.html">LogFactory</a> factory = (LogFactory) factories.get(classLoader);
<a name="730" href="#730">730</a>                 <strong class="jxr_keyword">if</strong> (factory != <strong class="jxr_keyword">null</strong>) {
<a name="731" href="#731">731</a>                     factory.release();
<a name="732" href="#732">732</a>                     factories.remove(classLoader);
<a name="733" href="#733">733</a>                 }
<a name="734" href="#734">734</a>             }
<a name="735" href="#735">735</a>         }
<a name="736" href="#736">736</a> 
<a name="737" href="#737">737</a>     }
<a name="738" href="#738">738</a> 
<a name="739" href="#739">739</a> 
<a name="740" href="#740">740</a>     <em class="jxr_javadoccomment">/**</em>
<a name="741" href="#741">741</a> <em class="jxr_javadoccomment">     * Release any internal references to previously created {@link LogFactory}</em>
<a name="742" href="#742">742</a> <em class="jxr_javadoccomment">     * instances, after calling the instance method &lt;code&gt;release()&lt;/code&gt; on</em>
<a name="743" href="#743">743</a> <em class="jxr_javadoccomment">     * each of them.  This is useful in environments like servlet containers,</em>
<a name="744" href="#744">744</a> <em class="jxr_javadoccomment">     * which implement application reloading by throwing away a ClassLoader.</em>
<a name="745" href="#745">745</a> <em class="jxr_javadoccomment">     * Dangling references to objects in that class loader would prevent</em>
<a name="746" href="#746">746</a> <em class="jxr_javadoccomment">     * garbage collection.</em>
<a name="747" href="#747">747</a> <em class="jxr_javadoccomment">     */</em>
<a name="748" href="#748">748</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">void</strong> releaseAll() {
<a name="749" href="#749">749</a> 
<a name="750" href="#750">750</a>         <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="751" href="#751">751</a>             logDiagnostic(<span class="jxr_string">"Releasing factory for all classloaders."</span>);
<a name="752" href="#752">752</a>         }
<a name="753" href="#753">753</a>         <strong class="jxr_keyword">synchronized</strong> (factories) {
<a name="754" href="#754">754</a>             Enumeration elements = factories.elements();
<a name="755" href="#755">755</a>             <strong class="jxr_keyword">while</strong> (elements.hasMoreElements()) {
<a name="756" href="#756">756</a>                 <a href="../../../../org/apache/commons/logging/LogFactory.html">LogFactory</a> element = (LogFactory) elements.nextElement();
<a name="757" href="#757">757</a>                 element.release();
<a name="758" href="#758">758</a>             }
<a name="759" href="#759">759</a>             factories.clear();
<a name="760" href="#760">760</a> 
<a name="761" href="#761">761</a>             <strong class="jxr_keyword">if</strong> (nullClassLoaderFactory != <strong class="jxr_keyword">null</strong>) {
<a name="762" href="#762">762</a>                 nullClassLoaderFactory.release();
<a name="763" href="#763">763</a>                 nullClassLoaderFactory = <strong class="jxr_keyword">null</strong>;
<a name="764" href="#764">764</a>             }
<a name="765" href="#765">765</a>         }
<a name="766" href="#766">766</a> 
<a name="767" href="#767">767</a>     }
<a name="768" href="#768">768</a> 
<a name="769" href="#769">769</a> 
<a name="770" href="#770">770</a>     <em class="jxr_comment">// ------------------------------------------------------ Protected Methods</em>
<a name="771" href="#771">771</a> 
<a name="772" href="#772">772</a>     <em class="jxr_javadoccomment">/**</em>
<a name="773" href="#773">773</a> <em class="jxr_javadoccomment">     * Safely get access to the classloader for the specified class.</em>
<a name="774" href="#774">774</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="775" href="#775">775</a> <em class="jxr_javadoccomment">     * Theoretically, calling getClassLoader can throw a security exception,</em>
<a name="776" href="#776">776</a> <em class="jxr_javadoccomment">     * and so should be done under an AccessController in order to provide</em>
<a name="777" href="#777">777</a> <em class="jxr_javadoccomment">     * maximum flexibility. However in practice people don't appear to use</em>
<a name="778" href="#778">778</a> <em class="jxr_javadoccomment">     * security policies that forbid getClassLoader calls. So for the moment</em>
<a name="779" href="#779">779</a> <em class="jxr_javadoccomment">     * all code is written to call this method rather than Class.getClassLoader,</em>
<a name="780" href="#780">780</a> <em class="jxr_javadoccomment">     * so that we could put AccessController stuff in this method without any</em>
<a name="781" href="#781">781</a> <em class="jxr_javadoccomment">     * disruption later if we need to.</em>
<a name="782" href="#782">782</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="783" href="#783">783</a> <em class="jxr_javadoccomment">     * Even when using an AccessController, however, this method can still</em>
<a name="784" href="#784">784</a> <em class="jxr_javadoccomment">     * throw SecurityException. Commons-logging basically relies on the</em>
<a name="785" href="#785">785</a> <em class="jxr_javadoccomment">     * ability to access classloaders, ie a policy that forbids all</em>
<a name="786" href="#786">786</a> <em class="jxr_javadoccomment">     * classloader access will also prevent commons-logging from working: </em>
<a name="787" href="#787">787</a> <em class="jxr_javadoccomment">     * currently this method will throw an exception preventing the entire app</em>
<a name="788" href="#788">788</a> <em class="jxr_javadoccomment">     * from starting up. Maybe it would be good to detect this situation and</em>
<a name="789" href="#789">789</a> <em class="jxr_javadoccomment">     * just disable all commons-logging? Not high priority though - as stated</em>
<a name="790" href="#790">790</a> <em class="jxr_javadoccomment">     * above, security policies that prevent classloader access aren't common.</em>
<a name="791" href="#791">791</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="792" href="#792">792</a> <em class="jxr_javadoccomment">     * Note that returning an object fetched via an AccessController would</em>
<a name="793" href="#793">793</a> <em class="jxr_javadoccomment">     * technically be a security flaw anyway; untrusted code that has access</em>
<a name="794" href="#794">794</a> <em class="jxr_javadoccomment">     * to a trusted JCL library could use it to fetch the classloader for</em>
<a name="795" href="#795">795</a> <em class="jxr_javadoccomment">     * a class even when forbidden to do so directly.</em>
<a name="796" href="#796">796</a> <em class="jxr_javadoccomment">     * </em>
<a name="797" href="#797">797</a> <em class="jxr_javadoccomment">     * @since 1.1</em>
<a name="798" href="#798">798</a> <em class="jxr_javadoccomment">     */</em>
<a name="799" href="#799">799</a>     <strong class="jxr_keyword">protected</strong> <strong class="jxr_keyword">static</strong> ClassLoader getClassLoader(Class clazz) {
<a name="800" href="#800">800</a>         <strong class="jxr_keyword">try</strong> {
<a name="801" href="#801">801</a>             <strong class="jxr_keyword">return</strong> clazz.getClassLoader();
<a name="802" href="#802">802</a>         } <strong class="jxr_keyword">catch</strong>(SecurityException ex) {
<a name="803" href="#803">803</a>             <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="804" href="#804">804</a>                 logDiagnostic(
<a name="805" href="#805">805</a>                         <span class="jxr_string">"Unable to get classloader for class '"</span> + clazz
<a name="806" href="#806">806</a>                         + <span class="jxr_string">"' due to security restrictions - "</span> + ex.getMessage());
<a name="807" href="#807">807</a>             }
<a name="808" href="#808">808</a>             <strong class="jxr_keyword">throw</strong> ex;
<a name="809" href="#809">809</a>         }
<a name="810" href="#810">810</a>     }
<a name="811" href="#811">811</a> 
<a name="812" href="#812">812</a>     <em class="jxr_javadoccomment">/**</em>
<a name="813" href="#813">813</a> <em class="jxr_javadoccomment">     * Returns the current context classloader.</em>
<a name="814" href="#814">814</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="815" href="#815">815</a> <em class="jxr_javadoccomment">     * In versions prior to 1.1, this method did not use an AccessController.</em>
<a name="816" href="#816">816</a> <em class="jxr_javadoccomment">     * In version 1.1, an AccessController wrapper was incorrectly added to</em>
<a name="817" href="#817">817</a> <em class="jxr_javadoccomment">     * this method, causing a minor security flaw.</em>
<a name="818" href="#818">818</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="819" href="#819">819</a> <em class="jxr_javadoccomment">     * In version 1.1.1 this change was reverted; this method no longer uses</em>
<a name="820" href="#820">820</a> <em class="jxr_javadoccomment">     * an AccessController. User code wishing to obtain the context classloader</em>
<a name="821" href="#821">821</a> <em class="jxr_javadoccomment">     * must invoke this method via AccessController.doPrivileged if it needs</em>
<a name="822" href="#822">822</a> <em class="jxr_javadoccomment">     * support for that.</em>
<a name="823" href="#823">823</a> <em class="jxr_javadoccomment">     *  </em>
<a name="824" href="#824">824</a> <em class="jxr_javadoccomment">     * @return the context classloader associated with the current thread,</em>
<a name="825" href="#825">825</a> <em class="jxr_javadoccomment">     * or null if security doesn't allow it.</em>
<a name="826" href="#826">826</a> <em class="jxr_javadoccomment">     * </em>
<a name="827" href="#827">827</a> <em class="jxr_javadoccomment">     * @throws LogConfigurationException if there was some weird error while</em>
<a name="828" href="#828">828</a> <em class="jxr_javadoccomment">     * attempting to get the context classloader.</em>
<a name="829" href="#829">829</a> <em class="jxr_javadoccomment">     * </em>
<a name="830" href="#830">830</a> <em class="jxr_javadoccomment">     * @throws SecurityException if the current java security policy doesn't</em>
<a name="831" href="#831">831</a> <em class="jxr_javadoccomment">     * allow this class to access the context classloader.</em>
<a name="832" href="#832">832</a> <em class="jxr_javadoccomment">     */</em>
<a name="833" href="#833">833</a>     <strong class="jxr_keyword">protected</strong> <strong class="jxr_keyword">static</strong> ClassLoader getContextClassLoader()
<a name="834" href="#834">834</a>         <strong class="jxr_keyword">throws</strong> <a href="../../../../org/apache/commons/logging/LogConfigurationException.html">LogConfigurationException</a> {
<a name="835" href="#835">835</a> 
<a name="836" href="#836">836</a>         <strong class="jxr_keyword">return</strong> directGetContextClassLoader();
<a name="837" href="#837">837</a>     }
<a name="838" href="#838">838</a> 
<a name="839" href="#839">839</a>     <em class="jxr_javadoccomment">/**</em>
<a name="840" href="#840">840</a> <em class="jxr_javadoccomment">     * Calls LogFactory.directGetContextClassLoader under the control of an</em>
<a name="841" href="#841">841</a> <em class="jxr_javadoccomment">     * AccessController class. This means that java code running under a</em>
<a name="842" href="#842">842</a> <em class="jxr_javadoccomment">     * security manager that forbids access to ClassLoaders will still work</em>
<a name="843" href="#843">843</a> <em class="jxr_javadoccomment">     * if this class is given appropriate privileges, even when the caller</em>
<a name="844" href="#844">844</a> <em class="jxr_javadoccomment">     * doesn't have such privileges. Without using an AccessController, the</em>
<a name="845" href="#845">845</a> <em class="jxr_javadoccomment">     * the entire call stack must have the privilege before the call is</em>
<a name="846" href="#846">846</a> <em class="jxr_javadoccomment">     * allowed.</em>
<a name="847" href="#847">847</a> <em class="jxr_javadoccomment">     *  </em>
<a name="848" href="#848">848</a> <em class="jxr_javadoccomment">     * @return the context classloader associated with the current thread,</em>
<a name="849" href="#849">849</a> <em class="jxr_javadoccomment">     * or null if security doesn't allow it.</em>
<a name="850" href="#850">850</a> <em class="jxr_javadoccomment">     * </em>
<a name="851" href="#851">851</a> <em class="jxr_javadoccomment">     * @throws LogConfigurationException if there was some weird error while</em>
<a name="852" href="#852">852</a> <em class="jxr_javadoccomment">     * attempting to get the context classloader.</em>
<a name="853" href="#853">853</a> <em class="jxr_javadoccomment">     * </em>
<a name="854" href="#854">854</a> <em class="jxr_javadoccomment">     * @throws SecurityException if the current java security policy doesn't</em>
<a name="855" href="#855">855</a> <em class="jxr_javadoccomment">     * allow this class to access the context classloader.</em>
<a name="856" href="#856">856</a> <em class="jxr_javadoccomment">     */</em>
<a name="857" href="#857">857</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> ClassLoader getContextClassLoaderInternal()
<a name="858" href="#858">858</a>     <strong class="jxr_keyword">throws</strong> <a href="../../../../org/apache/commons/logging/LogConfigurationException.html">LogConfigurationException</a> {
<a name="859" href="#859">859</a>         <strong class="jxr_keyword">return</strong> (ClassLoader)AccessController.doPrivileged(
<a name="860" href="#860">860</a>             <strong class="jxr_keyword">new</strong> PrivilegedAction() {
<a name="861" href="#861">861</a>                 <strong class="jxr_keyword">public</strong> Object run() {
<a name="862" href="#862">862</a>                     <strong class="jxr_keyword">return</strong> directGetContextClassLoader();
<a name="863" href="#863">863</a>                 }
<a name="864" href="#864">864</a>             });
<a name="865" href="#865">865</a>     }
<a name="866" href="#866">866</a> 
<a name="867" href="#867">867</a>     <em class="jxr_javadoccomment">/**</em>
<a name="868" href="#868">868</a> <em class="jxr_javadoccomment">     * Return the thread context class loader if available; otherwise return </em>
<a name="869" href="#869">869</a> <em class="jxr_javadoccomment">     * null. </em>
<a name="870" href="#870">870</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="871" href="#871">871</a> <em class="jxr_javadoccomment">     * Most/all code should call getContextClassLoaderInternal rather than</em>
<a name="872" href="#872">872</a> <em class="jxr_javadoccomment">     * calling this method directly.</em>
<a name="873" href="#873">873</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="874" href="#874">874</a> <em class="jxr_javadoccomment">     * The thread context class loader is available for JDK 1.2</em>
<a name="875" href="#875">875</a> <em class="jxr_javadoccomment">     * or later, if certain security conditions are met.</em>
<a name="876" href="#876">876</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="877" href="#877">877</a> <em class="jxr_javadoccomment">     * Note that no internal logging is done within this method because</em>
<a name="878" href="#878">878</a> <em class="jxr_javadoccomment">     * this method is called every time LogFactory.getLogger() is called,</em>
<a name="879" href="#879">879</a> <em class="jxr_javadoccomment">     * and we don't want too much output generated here.</em>
<a name="880" href="#880">880</a> <em class="jxr_javadoccomment">     * </em>
<a name="881" href="#881">881</a> <em class="jxr_javadoccomment">     * @exception LogConfigurationException if a suitable class loader</em>
<a name="882" href="#882">882</a> <em class="jxr_javadoccomment">     * cannot be identified.</em>
<a name="883" href="#883">883</a> <em class="jxr_javadoccomment">     * </em>
<a name="884" href="#884">884</a> <em class="jxr_javadoccomment">     * @exception SecurityException if the java security policy forbids</em>
<a name="885" href="#885">885</a> <em class="jxr_javadoccomment">     * access to the context classloader from one of the classes in the</em>
<a name="886" href="#886">886</a> <em class="jxr_javadoccomment">     * current call stack. </em>
<a name="887" href="#887">887</a> <em class="jxr_javadoccomment">     * @since 1.1</em>
<a name="888" href="#888">888</a> <em class="jxr_javadoccomment">     */</em>
<a name="889" href="#889">889</a>     <strong class="jxr_keyword">protected</strong> <strong class="jxr_keyword">static</strong> ClassLoader directGetContextClassLoader()
<a name="890" href="#890">890</a>         <strong class="jxr_keyword">throws</strong> <a href="../../../../org/apache/commons/logging/LogConfigurationException.html">LogConfigurationException</a>
<a name="891" href="#891">891</a>     {
<a name="892" href="#892">892</a>         ClassLoader classLoader = <strong class="jxr_keyword">null</strong>;
<a name="893" href="#893">893</a> 
<a name="894" href="#894">894</a>         <strong class="jxr_keyword">try</strong> {
<a name="895" href="#895">895</a>             <em class="jxr_comment">// Are we running on a JDK 1.2 or later system?</em>
<a name="896" href="#896">896</a>             Method method = Thread.<strong class="jxr_keyword">class</strong>.getMethod(<span class="jxr_string">"getContextClassLoader"</span>, 
<a name="897" href="#897">897</a>                     (Class[]) <strong class="jxr_keyword">null</strong>);
<a name="898" href="#898">898</a> 
<a name="899" href="#899">899</a>             <em class="jxr_comment">// Get the thread context class loader (if there is one)</em>
<a name="900" href="#900">900</a>             <strong class="jxr_keyword">try</strong> {
<a name="901" href="#901">901</a>                 classLoader = (ClassLoader)method.invoke(Thread.currentThread(), 
<a name="902" href="#902">902</a>                         (Object[]) <strong class="jxr_keyword">null</strong>);
<a name="903" href="#903">903</a>             } <strong class="jxr_keyword">catch</strong> (IllegalAccessException e) {
<a name="904" href="#904">904</a>                 <strong class="jxr_keyword">throw</strong> <strong class="jxr_keyword">new</strong> <a href="../../../../org/apache/commons/logging/LogConfigurationException.html">LogConfigurationException</a>
<a name="905" href="#905">905</a>                     (<span class="jxr_string">"Unexpected IllegalAccessException"</span>, e);
<a name="906" href="#906">906</a>             } <strong class="jxr_keyword">catch</strong> (InvocationTargetException e) {
<a name="907" href="#907">907</a>                 <em class="jxr_javadoccomment">/**</em>
<a name="908" href="#908">908</a> <em class="jxr_javadoccomment">                 * InvocationTargetException is thrown by 'invoke' when</em>
<a name="909" href="#909">909</a> <em class="jxr_javadoccomment">                 * the method being invoked (getContextClassLoader) throws</em>
<a name="910" href="#910">910</a> <em class="jxr_javadoccomment">                 * an exception.</em>
<a name="911" href="#911">911</a> <em class="jxr_javadoccomment">                 *</em>
<a name="912" href="#912">912</a> <em class="jxr_javadoccomment">                 * getContextClassLoader() throws SecurityException when</em>
<a name="913" href="#913">913</a> <em class="jxr_javadoccomment">                 * the context class loader isn't an ancestor of the</em>
<a name="914" href="#914">914</a> <em class="jxr_javadoccomment">                 * calling class's class loader, or if security</em>
<a name="915" href="#915">915</a> <em class="jxr_javadoccomment">                 * permissions are restricted.</em>
<a name="916" href="#916">916</a> <em class="jxr_javadoccomment">                 *</em>
<a name="917" href="#917">917</a> <em class="jxr_javadoccomment">                 * In the first case (not related), we want to ignore and</em>
<a name="918" href="#918">918</a> <em class="jxr_javadoccomment">                 * keep going.  We cannot help but also ignore the second</em>
<a name="919" href="#919">919</a> <em class="jxr_javadoccomment">                 * with the logic below, but other calls elsewhere (to</em>
<a name="920" href="#920">920</a> <em class="jxr_javadoccomment">                 * obtain a class loader) will trigger this exception where</em>
<a name="921" href="#921">921</a> <em class="jxr_javadoccomment">                 * we can make a distinction.</em>
<a name="922" href="#922">922</a> <em class="jxr_javadoccomment">                 */</em>
<a name="923" href="#923">923</a>                 <strong class="jxr_keyword">if</strong> (e.getTargetException() instanceof SecurityException) {
<a name="924" href="#924">924</a>                     ;  <em class="jxr_comment">// ignore</em>
<a name="925" href="#925">925</a>                 } <strong class="jxr_keyword">else</strong> {
<a name="926" href="#926">926</a>                     <em class="jxr_comment">// Capture 'e.getTargetException()' exception for details</em>
<a name="927" href="#927">927</a>                     <em class="jxr_comment">// alternate: log 'e.getTargetException()', and pass back 'e'.</em>
<a name="928" href="#928">928</a>                     <strong class="jxr_keyword">throw</strong> <strong class="jxr_keyword">new</strong> <a href="../../../../org/apache/commons/logging/LogConfigurationException.html">LogConfigurationException</a>
<a name="929" href="#929">929</a>                         (<span class="jxr_string">"Unexpected InvocationTargetException"</span>, e.getTargetException());
<a name="930" href="#930">930</a>                 }
<a name="931" href="#931">931</a>             }
<a name="932" href="#932">932</a>         } <strong class="jxr_keyword">catch</strong> (NoSuchMethodException e) {
<a name="933" href="#933">933</a>             <em class="jxr_comment">// Assume we are running on JDK 1.1</em>
<a name="934" href="#934">934</a>             classLoader = getClassLoader(LogFactory.<strong class="jxr_keyword">class</strong>);
<a name="935" href="#935">935</a> 
<a name="936" href="#936">936</a>             <em class="jxr_comment">// We deliberately don't log a message here to outputStream;</em>
<a name="937" href="#937">937</a>             <em class="jxr_comment">// this message would be output for every call to LogFactory.getLog()</em>
<a name="938" href="#938">938</a>             <em class="jxr_comment">// when running on JDK1.1</em>
<a name="939" href="#939">939</a>             <em class="jxr_comment">//</em>
<a name="940" href="#940">940</a>             <em class="jxr_comment">// if (outputStream != null) {</em>
<a name="941" href="#941">941</a>             <em class="jxr_comment">//    outputStream.println(</em>
<a name="942" href="#942">942</a>             <em class="jxr_comment">//        "Method Thread.getContextClassLoader does not exist;"</em>
<a name="943" href="#943">943</a>             <em class="jxr_comment">//         + " assuming this is JDK 1.1, and that the context"</em>
<a name="944" href="#944">944</a>             <em class="jxr_comment">//         + " classloader is the same as the class that loaded"</em>
<a name="945" href="#945">945</a>             <em class="jxr_comment">//         + " the concrete LogFactory class.");</em>
<a name="946" href="#946">946</a>             <em class="jxr_comment">// }</em>
<a name="947" href="#947">947</a>             
<a name="948" href="#948">948</a>         }
<a name="949" href="#949">949</a> 
<a name="950" href="#950">950</a>         <em class="jxr_comment">// Return the selected class loader</em>
<a name="951" href="#951">951</a>         <strong class="jxr_keyword">return</strong> classLoader;
<a name="952" href="#952">952</a>     }
<a name="953" href="#953">953</a> 
<a name="954" href="#954">954</a>     <em class="jxr_javadoccomment">/**</em>
<a name="955" href="#955">955</a> <em class="jxr_javadoccomment">     * Check cached factories (keyed by contextClassLoader)</em>
<a name="956" href="#956">956</a> <em class="jxr_javadoccomment">     *</em>
<a name="957" href="#957">957</a> <em class="jxr_javadoccomment">     * @param contextClassLoader is the context classloader associated</em>
<a name="958" href="#958">958</a> <em class="jxr_javadoccomment">     * with the current thread. This allows separate LogFactory objects</em>
<a name="959" href="#959">959</a> <em class="jxr_javadoccomment">     * per component within a container, provided each component has</em>
<a name="960" href="#960">960</a> <em class="jxr_javadoccomment">     * a distinct context classloader set. This parameter may be null</em>
<a name="961" href="#961">961</a> <em class="jxr_javadoccomment">     * in JDK1.1, and in embedded systems where jcl-using code is</em>
<a name="962" href="#962">962</a> <em class="jxr_javadoccomment">     * placed in the bootclasspath.</em>
<a name="963" href="#963">963</a> <em class="jxr_javadoccomment">     * </em>
<a name="964" href="#964">964</a> <em class="jxr_javadoccomment">     * @return the factory associated with the specified classloader if</em>
<a name="965" href="#965">965</a> <em class="jxr_javadoccomment">     * one has previously been created, or null if this is the first time</em>
<a name="966" href="#966">966</a> <em class="jxr_javadoccomment">     * we have seen this particular classloader.</em>
<a name="967" href="#967">967</a> <em class="jxr_javadoccomment">     */</em>
<a name="968" href="#968">968</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> <a href="../../../../org/apache/commons/logging/LogFactory.html">LogFactory</a> getCachedFactory(ClassLoader contextClassLoader)
<a name="969" href="#969">969</a>     {
<a name="970" href="#970">970</a>         <a href="../../../../org/apache/commons/logging/LogFactory.html">LogFactory</a> factory = <strong class="jxr_keyword">null</strong>;
<a name="971" href="#971">971</a> 
<a name="972" href="#972">972</a>         <strong class="jxr_keyword">if</strong> (contextClassLoader == <strong class="jxr_keyword">null</strong>) {
<a name="973" href="#973">973</a>             <em class="jxr_comment">// We have to handle this specially, as factories is a Hashtable</em>
<a name="974" href="#974">974</a>             <em class="jxr_comment">// and those don't accept null as a key value.</em>
<a name="975" href="#975">975</a>             <em class="jxr_comment">//</em>
<a name="976" href="#976">976</a>             <em class="jxr_comment">// nb: nullClassLoaderFactory might be null. That's ok.</em>
<a name="977" href="#977">977</a>             factory = nullClassLoaderFactory;
<a name="978" href="#978">978</a>         } <strong class="jxr_keyword">else</strong> {
<a name="979" href="#979">979</a>             factory = (LogFactory) factories.get(contextClassLoader);
<a name="980" href="#980">980</a>         }
<a name="981" href="#981">981</a> 
<a name="982" href="#982">982</a>         <strong class="jxr_keyword">return</strong> factory;
<a name="983" href="#983">983</a>     }
<a name="984" href="#984">984</a> 
<a name="985" href="#985">985</a>     <em class="jxr_javadoccomment">/**</em>
<a name="986" href="#986">986</a> <em class="jxr_javadoccomment">     * Remember this factory, so later calls to LogFactory.getCachedFactory</em>
<a name="987" href="#987">987</a> <em class="jxr_javadoccomment">     * can return the previously created object (together with all its</em>
<a name="988" href="#988">988</a> <em class="jxr_javadoccomment">     * cached Log objects).</em>
<a name="989" href="#989">989</a> <em class="jxr_javadoccomment">     *</em>
<a name="990" href="#990">990</a> <em class="jxr_javadoccomment">     * @param classLoader should be the current context classloader. Note that</em>
<a name="991" href="#991">991</a> <em class="jxr_javadoccomment">     * this can be null under some circumstances; this is ok.</em>
<a name="992" href="#992">992</a> <em class="jxr_javadoccomment">     *</em>
<a name="993" href="#993">993</a> <em class="jxr_javadoccomment">     * @param factory should be the factory to cache. This should never be null.</em>
<a name="994" href="#994">994</a> <em class="jxr_javadoccomment">     */</em>
<a name="995" href="#995">995</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">void</strong> cacheFactory(ClassLoader classLoader, <a href="../../../../org/apache/commons/logging/LogFactory.html">LogFactory</a> factory)
<a name="996" href="#996">996</a>     {
<a name="997" href="#997">997</a>         <em class="jxr_comment">// Ideally we would assert(factory != null) here. However reporting</em>
<a name="998" href="#998">998</a>         <em class="jxr_comment">// errors from within a logging implementation is a little tricky!</em>
<a name="999" href="#999">999</a> 
<a name="1000" href="#1000">1000</a>         <strong class="jxr_keyword">if</strong> (factory != <strong class="jxr_keyword">null</strong>) {
<a name="1001" href="#1001">1001</a>             <strong class="jxr_keyword">if</strong> (classLoader == <strong class="jxr_keyword">null</strong>) {
<a name="1002" href="#1002">1002</a>                 nullClassLoaderFactory = factory;
<a name="1003" href="#1003">1003</a>             } <strong class="jxr_keyword">else</strong> {
<a name="1004" href="#1004">1004</a>                 factories.put(classLoader, factory);
<a name="1005" href="#1005">1005</a>             }
<a name="1006" href="#1006">1006</a>         }
<a name="1007" href="#1007">1007</a>     }
<a name="1008" href="#1008">1008</a> 
<a name="1009" href="#1009">1009</a>     <em class="jxr_javadoccomment">/**</em>
<a name="1010" href="#1010">1010</a> <em class="jxr_javadoccomment">     * Return a new instance of the specified &lt;code&gt;LogFactory&lt;/code&gt;</em>
<a name="1011" href="#1011">1011</a> <em class="jxr_javadoccomment">     * implementation class, loaded by the specified class loader.</em>
<a name="1012" href="#1012">1012</a> <em class="jxr_javadoccomment">     * If that fails, try the class loader used to load this</em>
<a name="1013" href="#1013">1013</a> <em class="jxr_javadoccomment">     * (abstract) LogFactory.</em>
<a name="1014" href="#1014">1014</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="1015" href="#1015">1015</a> <em class="jxr_javadoccomment">     * &lt;h2&gt;ClassLoader conflicts&lt;/h2&gt;</em>
<a name="1016" href="#1016">1016</a> <em class="jxr_javadoccomment">     * Note that there can be problems if the specified ClassLoader is not the </em>
<a name="1017" href="#1017">1017</a> <em class="jxr_javadoccomment">     * same as the classloader that loaded this class, ie when loading a</em>
<a name="1018" href="#1018">1018</a> <em class="jxr_javadoccomment">     * concrete LogFactory subclass via a context classloader.</em>
<a name="1019" href="#1019">1019</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="1020" href="#1020">1020</a> <em class="jxr_javadoccomment">     * The problem is the same one that can occur when loading a concrete Log</em>
<a name="1021" href="#1021">1021</a> <em class="jxr_javadoccomment">     * subclass via a context classloader.</em>
<a name="1022" href="#1022">1022</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="1023" href="#1023">1023</a> <em class="jxr_javadoccomment">     * The problem occurs when code running in the context classloader calls</em>
<a name="1024" href="#1024">1024</a> <em class="jxr_javadoccomment">     * class X which was loaded via a parent classloader, and class X then calls</em>
<a name="1025" href="#1025">1025</a> <em class="jxr_javadoccomment">     * LogFactory.getFactory (either directly or via LogFactory.getLog). Because</em>
<a name="1026" href="#1026">1026</a> <em class="jxr_javadoccomment">     * class X was loaded via the parent, it binds to LogFactory loaded via</em>
<a name="1027" href="#1027">1027</a> <em class="jxr_javadoccomment">     * the parent. When the code in this method finds some LogFactoryYYYY</em>
<a name="1028" href="#1028">1028</a> <em class="jxr_javadoccomment">     * class in the child (context) classloader, and there also happens to be a</em>
<a name="1029" href="#1029">1029</a> <em class="jxr_javadoccomment">     * LogFactory class defined in the child classloader, then LogFactoryYYYY</em>
<a name="1030" href="#1030">1030</a> <em class="jxr_javadoccomment">     * will be bound to LogFactory@childloader. It cannot be cast to</em>
<a name="1031" href="#1031">1031</a> <em class="jxr_javadoccomment">     * LogFactory@parentloader, ie this method cannot return the object as</em>
<a name="1032" href="#1032">1032</a> <em class="jxr_javadoccomment">     * the desired type. Note that it doesn't matter if the LogFactory class</em>
<a name="1033" href="#1033">1033</a> <em class="jxr_javadoccomment">     * in the child classloader is identical to the LogFactory class in the</em>
<a name="1034" href="#1034">1034</a> <em class="jxr_javadoccomment">     * parent classloader, they are not compatible.</em>
<a name="1035" href="#1035">1035</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="1036" href="#1036">1036</a> <em class="jxr_javadoccomment">     * The solution taken here is to simply print out an error message when</em>
<a name="1037" href="#1037">1037</a> <em class="jxr_javadoccomment">     * this occurs then throw an exception. The deployer of the application</em>
<a name="1038" href="#1038">1038</a> <em class="jxr_javadoccomment">     * must ensure they remove all occurrences of the LogFactory class from</em>
<a name="1039" href="#1039">1039</a> <em class="jxr_javadoccomment">     * the child classloader in order to resolve the issue. Note that they</em>
<a name="1040" href="#1040">1040</a> <em class="jxr_javadoccomment">     * do not have to move the custom LogFactory subclass; that is ok as</em>
<a name="1041" href="#1041">1041</a> <em class="jxr_javadoccomment">     * long as the only LogFactory class it can find to bind to is in the</em>
<a name="1042" href="#1042">1042</a> <em class="jxr_javadoccomment">     * parent classloader.</em>
<a name="1043" href="#1043">1043</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="1044" href="#1044">1044</a> <em class="jxr_javadoccomment">     * @param factoryClass Fully qualified name of the &lt;code&gt;LogFactory&lt;/code&gt;</em>
<a name="1045" href="#1045">1045</a> <em class="jxr_javadoccomment">     *  implementation class</em>
<a name="1046" href="#1046">1046</a> <em class="jxr_javadoccomment">     * @param classLoader ClassLoader from which to load this class</em>
<a name="1047" href="#1047">1047</a> <em class="jxr_javadoccomment">     * @param contextClassLoader is the context that this new factory will</em>
<a name="1048" href="#1048">1048</a> <em class="jxr_javadoccomment">     * manage logging for.</em>
<a name="1049" href="#1049">1049</a> <em class="jxr_javadoccomment">     *</em>
<a name="1050" href="#1050">1050</a> <em class="jxr_javadoccomment">     * @exception LogConfigurationException if a suitable instance</em>
<a name="1051" href="#1051">1051</a> <em class="jxr_javadoccomment">     *  cannot be created</em>
<a name="1052" href="#1052">1052</a> <em class="jxr_javadoccomment">     * @since 1.1</em>
<a name="1053" href="#1053">1053</a> <em class="jxr_javadoccomment">     */</em>
<a name="1054" href="#1054">1054</a>     <strong class="jxr_keyword">protected</strong> <strong class="jxr_keyword">static</strong> <a href="../../../../org/apache/commons/logging/LogFactory.html">LogFactory</a> newFactory(<strong class="jxr_keyword">final</strong> String factoryClass,
<a name="1055" href="#1055">1055</a>                                            <strong class="jxr_keyword">final</strong> ClassLoader classLoader,
<a name="1056" href="#1056">1056</a>                                            <strong class="jxr_keyword">final</strong> ClassLoader contextClassLoader)
<a name="1057" href="#1057">1057</a>         <strong class="jxr_keyword">throws</strong> <a href="../../../../org/apache/commons/logging/LogConfigurationException.html">LogConfigurationException</a>
<a name="1058" href="#1058">1058</a>     {
<a name="1059" href="#1059">1059</a>         <em class="jxr_comment">// Note that any unchecked exceptions thrown by the createFactory</em>
<a name="1060" href="#1060">1060</a>         <em class="jxr_comment">// method will propagate out of this method; in particular a</em>
<a name="1061" href="#1061">1061</a>         <em class="jxr_comment">// ClassCastException can be thrown.</em>
<a name="1062" href="#1062">1062</a>         Object result = AccessController.doPrivileged(
<a name="1063" href="#1063">1063</a>             <strong class="jxr_keyword">new</strong> PrivilegedAction() {
<a name="1064" href="#1064">1064</a>                 <strong class="jxr_keyword">public</strong> Object run() {
<a name="1065" href="#1065">1065</a>                     <strong class="jxr_keyword">return</strong> createFactory(factoryClass, classLoader);
<a name="1066" href="#1066">1066</a>                 }
<a name="1067" href="#1067">1067</a>             });
<a name="1068" href="#1068">1068</a> 
<a name="1069" href="#1069">1069</a>         <strong class="jxr_keyword">if</strong> (result instanceof LogConfigurationException) {
<a name="1070" href="#1070">1070</a>             <a href="../../../../org/apache/commons/logging/LogConfigurationException.html">LogConfigurationException</a> ex = (LogConfigurationException) result;
<a name="1071" href="#1071">1071</a>             <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="1072" href="#1072">1072</a>                 logDiagnostic(
<a name="1073" href="#1073">1073</a>                         <span class="jxr_string">"An error occurred while loading the factory class:"</span>
<a name="1074" href="#1074">1074</a>                         + ex.getMessage());
<a name="1075" href="#1075">1075</a>             }
<a name="1076" href="#1076">1076</a>             <strong class="jxr_keyword">throw</strong> ex;
<a name="1077" href="#1077">1077</a>         }
<a name="1078" href="#1078">1078</a>         <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="1079" href="#1079">1079</a>             logDiagnostic(
<a name="1080" href="#1080">1080</a>                     <span class="jxr_string">"Created object "</span> + objectId(result)
<a name="1081" href="#1081">1081</a>                     + <span class="jxr_string">" to manage classloader "</span> + objectId(contextClassLoader));
<a name="1082" href="#1082">1082</a>         }
<a name="1083" href="#1083">1083</a>         <strong class="jxr_keyword">return</strong> (LogFactory)result;
<a name="1084" href="#1084">1084</a>     }
<a name="1085" href="#1085">1085</a> 
<a name="1086" href="#1086">1086</a>     <em class="jxr_javadoccomment">/**</em>
<a name="1087" href="#1087">1087</a> <em class="jxr_javadoccomment">     * Method provided for backwards compatibility; see newFactory version that</em>
<a name="1088" href="#1088">1088</a> <em class="jxr_javadoccomment">     * takes 3 parameters.</em>
<a name="1089" href="#1089">1089</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="1090" href="#1090">1090</a> <em class="jxr_javadoccomment">     * This method would only ever be called in some rather odd situation.</em>
<a name="1091" href="#1091">1091</a> <em class="jxr_javadoccomment">     * Note that this method is static, so overriding in a subclass doesn't</em>
<a name="1092" href="#1092">1092</a> <em class="jxr_javadoccomment">     * have any effect unless this method is called from a method in that</em>
<a name="1093" href="#1093">1093</a> <em class="jxr_javadoccomment">     * subclass. However this method only makes sense to use from the</em>
<a name="1094" href="#1094">1094</a> <em class="jxr_javadoccomment">     * getFactory method, and as that is almost always invoked via</em>
<a name="1095" href="#1095">1095</a> <em class="jxr_javadoccomment">     * LogFactory.getFactory, any custom definition in a subclass would be</em>
<a name="1096" href="#1096">1096</a> <em class="jxr_javadoccomment">     * pointless. Only a class with a custom getFactory method, then invoked</em>
<a name="1097" href="#1097">1097</a> <em class="jxr_javadoccomment">     * directly via CustomFactoryImpl.getFactory or similar would ever call</em>
<a name="1098" href="#1098">1098</a> <em class="jxr_javadoccomment">     * this. Anyway, it's here just in case, though the "managed class loader"</em>
<a name="1099" href="#1099">1099</a> <em class="jxr_javadoccomment">     * value output to the diagnostics will not report the correct value.</em>
<a name="1100" href="#1100">1100</a> <em class="jxr_javadoccomment">     */</em>
<a name="1101" href="#1101">1101</a>     <strong class="jxr_keyword">protected</strong> <strong class="jxr_keyword">static</strong> <a href="../../../../org/apache/commons/logging/LogFactory.html">LogFactory</a> newFactory(<strong class="jxr_keyword">final</strong> String factoryClass,
<a name="1102" href="#1102">1102</a>                                            <strong class="jxr_keyword">final</strong> ClassLoader classLoader) {
<a name="1103" href="#1103">1103</a>         <strong class="jxr_keyword">return</strong> newFactory(factoryClass, classLoader, <strong class="jxr_keyword">null</strong>);
<a name="1104" href="#1104">1104</a>     }
<a name="1105" href="#1105">1105</a> 
<a name="1106" href="#1106">1106</a>     <em class="jxr_javadoccomment">/**</em>
<a name="1107" href="#1107">1107</a> <em class="jxr_javadoccomment">     * Implements the operations described in the javadoc for newFactory.</em>
<a name="1108" href="#1108">1108</a> <em class="jxr_javadoccomment">     * </em>
<a name="1109" href="#1109">1109</a> <em class="jxr_javadoccomment">     * @param factoryClass</em>
<a name="1110" href="#1110">1110</a> <em class="jxr_javadoccomment">     * </em>
<a name="1111" href="#1111">1111</a> <em class="jxr_javadoccomment">     * @param classLoader used to load the specified factory class. This is</em>
<a name="1112" href="#1112">1112</a> <em class="jxr_javadoccomment">     * expected to be either the TCCL or the classloader which loaded this</em>
<a name="1113" href="#1113">1113</a> <em class="jxr_javadoccomment">     * class. Note that the classloader which loaded this class might be</em>
<a name="1114" href="#1114">1114</a> <em class="jxr_javadoccomment">     * "null" (ie the bootloader) for embedded systems.</em>
<a name="1115" href="#1115">1115</a> <em class="jxr_javadoccomment">     * </em>
<a name="1116" href="#1116">1116</a> <em class="jxr_javadoccomment">     * @return either a LogFactory object or a LogConfigurationException object.</em>
<a name="1117" href="#1117">1117</a> <em class="jxr_javadoccomment">     * @since 1.1</em>
<a name="1118" href="#1118">1118</a> <em class="jxr_javadoccomment">     */</em>
<a name="1119" href="#1119">1119</a>     <strong class="jxr_keyword">protected</strong> <strong class="jxr_keyword">static</strong> Object createFactory(String factoryClass, ClassLoader classLoader) {
<a name="1120" href="#1120">1120</a> 
<a name="1121" href="#1121">1121</a>         <em class="jxr_comment">// This will be used to diagnose bad configurations</em>
<a name="1122" href="#1122">1122</a>         <em class="jxr_comment">// and allow a useful message to be sent to the user</em>
<a name="1123" href="#1123">1123</a>         Class logFactoryClass = <strong class="jxr_keyword">null</strong>;
<a name="1124" href="#1124">1124</a>         <strong class="jxr_keyword">try</strong> {
<a name="1125" href="#1125">1125</a>             <strong class="jxr_keyword">if</strong> (classLoader != <strong class="jxr_keyword">null</strong>) {
<a name="1126" href="#1126">1126</a>                 <strong class="jxr_keyword">try</strong> {
<a name="1127" href="#1127">1127</a>                     <em class="jxr_comment">// First the given class loader param (thread class loader)</em>
<a name="1128" href="#1128">1128</a> 
<a name="1129" href="#1129">1129</a>                     <em class="jxr_comment">// Warning: must typecast here &amp; allow exception</em>
<a name="1130" href="#1130">1130</a>                     <em class="jxr_comment">// to be generated/caught &amp; recast properly.</em>
<a name="1131" href="#1131">1131</a>                     logFactoryClass = classLoader.loadClass(factoryClass);
<a name="1132" href="#1132">1132</a>                     <strong class="jxr_keyword">if</strong> (LogFactory.<strong class="jxr_keyword">class</strong>.isAssignableFrom(logFactoryClass)) {
<a name="1133" href="#1133">1133</a>                         <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="1134" href="#1134">1134</a>                             logDiagnostic(
<a name="1135" href="#1135">1135</a>                                     <span class="jxr_string">"Loaded class "</span> + logFactoryClass.getName()
<a name="1136" href="#1136">1136</a>                                     + <span class="jxr_string">" from classloader "</span> + objectId(classLoader));
<a name="1137" href="#1137">1137</a>                         }
<a name="1138" href="#1138">1138</a>                     } <strong class="jxr_keyword">else</strong> {
<a name="1139" href="#1139">1139</a>                         <em class="jxr_comment">//</em>
<a name="1140" href="#1140">1140</a>                         <em class="jxr_comment">// This indicates a problem with the ClassLoader tree.</em>
<a name="1141" href="#1141">1141</a>                         <em class="jxr_comment">// An incompatible ClassLoader was used to load the </em>
<a name="1142" href="#1142">1142</a>                         <em class="jxr_comment">// implementation. </em>
<a name="1143" href="#1143">1143</a>                         <em class="jxr_comment">// As the same classes</em>
<a name="1144" href="#1144">1144</a>                         <em class="jxr_comment">// must be available in multiple class loaders,</em>
<a name="1145" href="#1145">1145</a>                         <em class="jxr_comment">// it is very likely that multiple JCL jars are present.</em>
<a name="1146" href="#1146">1146</a>                         <em class="jxr_comment">// The most likely fix for this</em>
<a name="1147" href="#1147">1147</a>                         <em class="jxr_comment">// problem is to remove the extra JCL jars from the </em>
<a name="1148" href="#1148">1148</a>                         <em class="jxr_comment">// ClassLoader hierarchy. </em>
<a name="1149" href="#1149">1149</a>                         <em class="jxr_comment">//</em>
<a name="1150" href="#1150">1150</a>                         <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="1151" href="#1151">1151</a>                             logDiagnostic(
<a name="1152" href="#1152">1152</a>                                     <span class="jxr_string">"Factory class "</span> + logFactoryClass.getName()
<a name="1153" href="#1153">1153</a>                                 + <span class="jxr_string">" loaded from classloader "</span> + objectId(logFactoryClass.getClassLoader())
<a name="1154" href="#1154">1154</a>                                 + <span class="jxr_string">" does not extend '"</span> + LogFactory.<strong class="jxr_keyword">class</strong>.getName()
<a name="1155" href="#1155">1155</a>                                 + <span class="jxr_string">"' as loaded by this classloader."</span>);
<a name="1156" href="#1156">1156</a>                             logHierarchy(<span class="jxr_string">"[BAD CL TREE] "</span>, classLoader);
<a name="1157" href="#1157">1157</a>                         }
<a name="1158" href="#1158">1158</a>                     }
<a name="1159" href="#1159">1159</a>                     
<a name="1160" href="#1160">1160</a>                     <strong class="jxr_keyword">return</strong> (LogFactory) logFactoryClass.newInstance();
<a name="1161" href="#1161">1161</a> 
<a name="1162" href="#1162">1162</a>                 } <strong class="jxr_keyword">catch</strong> (ClassNotFoundException ex) {
<a name="1163" href="#1163">1163</a>                     <strong class="jxr_keyword">if</strong> (classLoader == thisClassLoader) {
<a name="1164" href="#1164">1164</a>                         <em class="jxr_comment">// Nothing more to try, onwards.</em>
<a name="1165" href="#1165">1165</a>                         <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="1166" href="#1166">1166</a>                             logDiagnostic(
<a name="1167" href="#1167">1167</a>                                     <span class="jxr_string">"Unable to locate any class called '"</span> + factoryClass
<a name="1168" href="#1168">1168</a>                                     + <span class="jxr_string">"' via classloader "</span> + objectId(classLoader));
<a name="1169" href="#1169">1169</a>                         }
<a name="1170" href="#1170">1170</a>                         <strong class="jxr_keyword">throw</strong> ex;
<a name="1171" href="#1171">1171</a>                     }
<a name="1172" href="#1172">1172</a>                     <em class="jxr_comment">// ignore exception, continue</em>
<a name="1173" href="#1173">1173</a>                 } <strong class="jxr_keyword">catch</strong> (NoClassDefFoundError e) {
<a name="1174" href="#1174">1174</a>                     <strong class="jxr_keyword">if</strong> (classLoader == thisClassLoader) {
<a name="1175" href="#1175">1175</a>                         <em class="jxr_comment">// Nothing more to try, onwards.</em>
<a name="1176" href="#1176">1176</a>                         <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="1177" href="#1177">1177</a>                             logDiagnostic(
<a name="1178" href="#1178">1178</a>                                     <span class="jxr_string">"Class '"</span> + factoryClass + <span class="jxr_string">"' cannot be loaded"</span>
<a name="1179" href="#1179">1179</a>                                     + <span class="jxr_string">" via classloader "</span> + objectId(classLoader)
<a name="1180" href="#1180">1180</a>                                     + <span class="jxr_string">" - it depends on some other class that cannot"</span>
<a name="1181" href="#1181">1181</a>                                     + <span class="jxr_string">" be found."</span>);
<a name="1182" href="#1182">1182</a>                         }
<a name="1183" href="#1183">1183</a>                         <strong class="jxr_keyword">throw</strong> e;
<a name="1184" href="#1184">1184</a>                     }
<a name="1185" href="#1185">1185</a>                     <em class="jxr_comment">// ignore exception, continue</em>
<a name="1186" href="#1186">1186</a>                 } <strong class="jxr_keyword">catch</strong>(ClassCastException e) {
<a name="1187" href="#1187">1187</a>                     <strong class="jxr_keyword">if</strong> (classLoader == thisClassLoader) {
<a name="1188" href="#1188">1188</a>                         <em class="jxr_comment">// There's no point in falling through to the code below that</em>
<a name="1189" href="#1189">1189</a>                         <em class="jxr_comment">// tries again with thisClassLoader, because we've just tried</em>
<a name="1190" href="#1190">1190</a>                         <em class="jxr_comment">// loading with that loader (not the TCCL). Just throw an</em>
<a name="1191" href="#1191">1191</a>                         <em class="jxr_comment">// appropriate exception here.</em>
<a name="1192" href="#1192">1192</a> 
<a name="1193" href="#1193">1193</a>                         <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">boolean</strong> implementsLogFactory = implementsLogFactory(logFactoryClass);
<a name="1194" href="#1194">1194</a>                         
<a name="1195" href="#1195">1195</a>                         <em class="jxr_comment">//</em>
<a name="1196" href="#1196">1196</a>                         <em class="jxr_comment">// Construct a good message: users may not actual expect that a custom implementation </em>
<a name="1197" href="#1197">1197</a>                         <em class="jxr_comment">// has been specified. Several well known containers use this mechanism to adapt JCL </em>
<a name="1198" href="#1198">1198</a>                         <em class="jxr_comment">// to their native logging system. </em>
<a name="1199" href="#1199">1199</a>                         <em class="jxr_comment">// </em>
<a name="1200" href="#1200">1200</a>                         String msg = 
<a name="1201" href="#1201">1201</a>                             <span class="jxr_string">"The application has specified that a custom LogFactory implementation should be used but "</span> +
<a name="1202" href="#1202">1202</a>                             <span class="jxr_string">"Class '"</span> + factoryClass + <span class="jxr_string">"' cannot be converted to '"</span>
<a name="1203" href="#1203">1203</a>                             + LogFactory.<strong class="jxr_keyword">class</strong>.getName() + <span class="jxr_string">"'. "</span>;
<a name="1204" href="#1204">1204</a>                         <strong class="jxr_keyword">if</strong> (implementsLogFactory) {
<a name="1205" href="#1205">1205</a>                             msg = msg + <span class="jxr_string">"The conflict is caused by the presence of multiple LogFactory classes in incompatible classloaders. "</span> +
<a name="1206" href="#1206">1206</a>                                 <span class="jxr_string">"Background can be found in http://commons.apache.org/logging/tech.html. "</span> +
<a name="1207" href="#1207">1207</a>                                 <span class="jxr_string">"If you have not explicitly specified a custom LogFactory then it is likely that "</span> +
<a name="1208" href="#1208">1208</a>                                 <span class="jxr_string">"the container has set one without your knowledge. "</span> +
<a name="1209" href="#1209">1209</a>                                 <span class="jxr_string">"In this case, consider using the commons-logging-adapters.jar file or "</span> +
<a name="1210" href="#1210">1210</a>                                 <span class="jxr_string">"specifying the standard LogFactory from the command line. "</span>;
<a name="1211" href="#1211">1211</a>                         } <strong class="jxr_keyword">else</strong> {
<a name="1212" href="#1212">1212</a>                             msg = msg + <span class="jxr_string">"Please check the custom implementation. "</span>;
<a name="1213" href="#1213">1213</a>                         }
<a name="1214" href="#1214">1214</a>                         msg = msg + <span class="jxr_string">"Help can be found @http://commons.apache.org/logging/troubleshooting.html."</span>;
<a name="1215" href="#1215">1215</a>                         
<a name="1216" href="#1216">1216</a>                         <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="1217" href="#1217">1217</a>                             logDiagnostic(msg);
<a name="1218" href="#1218">1218</a>                         }
<a name="1219" href="#1219">1219</a>                         
<a name="1220" href="#1220">1220</a>                         ClassCastException ex = <strong class="jxr_keyword">new</strong> ClassCastException(msg);
<a name="1221" href="#1221">1221</a>                         <strong class="jxr_keyword">throw</strong> ex;
<a name="1222" href="#1222">1222</a>                     }
<a name="1223" href="#1223">1223</a>                     
<a name="1224" href="#1224">1224</a>                     <em class="jxr_comment">// Ignore exception, continue. Presumably the classloader was the</em>
<a name="1225" href="#1225">1225</a>                     <em class="jxr_comment">// TCCL; the code below will try to load the class via thisClassLoader.</em>
<a name="1226" href="#1226">1226</a>                     <em class="jxr_comment">// This will handle the case where the original calling class is in</em>
<a name="1227" href="#1227">1227</a>                     <em class="jxr_comment">// a shared classpath but the TCCL has a copy of LogFactory and the</em>
<a name="1228" href="#1228">1228</a>                     <em class="jxr_comment">// specified LogFactory implementation; we will fall back to using the</em>
<a name="1229" href="#1229">1229</a>                     <em class="jxr_comment">// LogFactory implementation from the same classloader as this class.</em>
<a name="1230" href="#1230">1230</a>                     <em class="jxr_comment">//</em>
<a name="1231" href="#1231">1231</a>                     <em class="jxr_comment">// Issue: this doesn't handle the reverse case, where this LogFactory</em>
<a name="1232" href="#1232">1232</a>                     <em class="jxr_comment">// is in the webapp, and the specified LogFactory implementation is</em>
<a name="1233" href="#1233">1233</a>                     <em class="jxr_comment">// in a shared classpath. In that case:</em>
<a name="1234" href="#1234">1234</a>                     <em class="jxr_comment">// (a) the class really does implement LogFactory (bad log msg above)</em>
<a name="1235" href="#1235">1235</a>                     <em class="jxr_comment">// (b) the fallback code will result in exactly the same problem.</em>
<a name="1236" href="#1236">1236</a>                 }
<a name="1237" href="#1237">1237</a>             }
<a name="1238" href="#1238">1238</a> 
<a name="1239" href="#1239">1239</a>             <em class="jxr_comment">/*<em class="jxr_comment"> At this point, either classLoader == null, OR</em></em>
<a name="1240" href="#1240">1240</a> <em class="jxr_comment">             * classLoader was unable to load factoryClass.</em>
<a name="1241" href="#1241">1241</a> <em class="jxr_comment">             *</em>
<a name="1242" href="#1242">1242</a> <em class="jxr_comment">             * In either case, we call Class.forName, which is equivalent</em>
<a name="1243" href="#1243">1243</a> <em class="jxr_comment">             * to LogFactory.class.getClassLoader().load(name), ie we ignore</em>
<a name="1244" href="#1244">1244</a> <em class="jxr_comment">             * the classloader parameter the caller passed, and fall back</em>
<a name="1245" href="#1245">1245</a> <em class="jxr_comment">             * to trying the classloader associated with this class. See the</em>
<a name="1246" href="#1246">1246</a> <em class="jxr_comment">             * javadoc for the newFactory method for more info on the </em>
<a name="1247" href="#1247">1247</a> <em class="jxr_comment">             * consequences of this.</em>
<a name="1248" href="#1248">1248</a> <em class="jxr_comment">             *</em>
<a name="1249" href="#1249">1249</a> <em class="jxr_comment">             * Notes:</em>
<a name="1250" href="#1250">1250</a> <em class="jxr_comment">             * * LogFactory.class.getClassLoader() may return 'null'</em>
<a name="1251" href="#1251">1251</a> <em class="jxr_comment">             *   if LogFactory is loaded by the bootstrap classloader.</em>
<a name="1252" href="#1252">1252</a> <em class="jxr_comment">             */</em>
<a name="1253" href="#1253">1253</a>             <em class="jxr_comment">// Warning: must typecast here &amp; allow exception</em>
<a name="1254" href="#1254">1254</a>             <em class="jxr_comment">// to be generated/caught &amp; recast properly.</em>
<a name="1255" href="#1255">1255</a>             <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="1256" href="#1256">1256</a>                 logDiagnostic(
<a name="1257" href="#1257">1257</a>                     <span class="jxr_string">"Unable to load factory class via classloader "</span> 
<a name="1258" href="#1258">1258</a>                     + objectId(classLoader)
<a name="1259" href="#1259">1259</a>                     + <span class="jxr_string">" - trying the classloader associated with this LogFactory."</span>);
<a name="1260" href="#1260">1260</a>             }
<a name="1261" href="#1261">1261</a>             logFactoryClass = Class.forName(factoryClass);
<a name="1262" href="#1262">1262</a>             <strong class="jxr_keyword">return</strong> (LogFactory) logFactoryClass.newInstance();
<a name="1263" href="#1263">1263</a>         } <strong class="jxr_keyword">catch</strong> (Exception e) {
<a name="1264" href="#1264">1264</a>             <em class="jxr_comment">// Check to see if we've got a bad configuration</em>
<a name="1265" href="#1265">1265</a>             <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="1266" href="#1266">1266</a>                 logDiagnostic(<span class="jxr_string">"Unable to create LogFactory instance."</span>);
<a name="1267" href="#1267">1267</a>             }
<a name="1268" href="#1268">1268</a>             <strong class="jxr_keyword">if</strong> (logFactoryClass != <strong class="jxr_keyword">null</strong>
<a name="1269" href="#1269">1269</a>                 &amp;&amp; !LogFactory.<strong class="jxr_keyword">class</strong>.isAssignableFrom(logFactoryClass)) {
<a name="1270" href="#1270">1270</a>                 
<a name="1271" href="#1271">1271</a>                 <strong class="jxr_keyword">return</strong> <strong class="jxr_keyword">new</strong> <a href="../../../../org/apache/commons/logging/LogConfigurationException.html">LogConfigurationException</a>(
<a name="1272" href="#1272">1272</a>                     <span class="jxr_string">"The chosen LogFactory implementation does not extend LogFactory."</span>
<a name="1273" href="#1273">1273</a>                     + <span class="jxr_string">" Please check your configuration."</span>,
<a name="1274" href="#1274">1274</a>                     e);
<a name="1275" href="#1275">1275</a>             }
<a name="1276" href="#1276">1276</a>             <strong class="jxr_keyword">return</strong> <strong class="jxr_keyword">new</strong> <a href="../../../../org/apache/commons/logging/LogConfigurationException.html">LogConfigurationException</a>(e);
<a name="1277" href="#1277">1277</a>         }
<a name="1278" href="#1278">1278</a>     }
<a name="1279" href="#1279">1279</a> 
<a name="1280" href="#1280">1280</a>     <em class="jxr_javadoccomment">/**</em>
<a name="1281" href="#1281">1281</a> <em class="jxr_javadoccomment">     * Determines whether the given class actually implements &lt;code&gt;LogFactory&lt;/code&gt;.</em>
<a name="1282" href="#1282">1282</a> <em class="jxr_javadoccomment">     * Diagnostic information is also logged.</em>
<a name="1283" href="#1283">1283</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="1284" href="#1284">1284</a> <em class="jxr_javadoccomment">     * &lt;strong&gt;Usage:&lt;/strong&gt; to diagnose whether a classloader conflict is the cause</em>
<a name="1285" href="#1285">1285</a> <em class="jxr_javadoccomment">     * of incompatibility. The test used is whether the class is assignable from</em>
<a name="1286" href="#1286">1286</a> <em class="jxr_javadoccomment">     * the &lt;code&gt;LogFactory&lt;/code&gt; class loaded by the class's classloader.</em>
<a name="1287" href="#1287">1287</a> <em class="jxr_javadoccomment">     * @param logFactoryClass &lt;code&gt;Class&lt;/code&gt; which may implement &lt;code&gt;LogFactory&lt;/code&gt;</em>
<a name="1288" href="#1288">1288</a> <em class="jxr_javadoccomment">     * @return true if the &lt;code&gt;logFactoryClass&lt;/code&gt; does extend</em>
<a name="1289" href="#1289">1289</a> <em class="jxr_javadoccomment">     * &lt;code&gt;LogFactory&lt;/code&gt; when that class is loaded via the same</em>
<a name="1290" href="#1290">1290</a> <em class="jxr_javadoccomment">     * classloader that loaded the &lt;code&gt;logFactoryClass&lt;/code&gt;.</em>
<a name="1291" href="#1291">1291</a> <em class="jxr_javadoccomment">     */</em>
<a name="1292" href="#1292">1292</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">boolean</strong> implementsLogFactory(Class logFactoryClass) {
<a name="1293" href="#1293">1293</a>         <strong class="jxr_keyword">boolean</strong> implementsLogFactory = false;
<a name="1294" href="#1294">1294</a>         <strong class="jxr_keyword">if</strong> (logFactoryClass != <strong class="jxr_keyword">null</strong>) {
<a name="1295" href="#1295">1295</a>             <strong class="jxr_keyword">try</strong> {
<a name="1296" href="#1296">1296</a>                 ClassLoader logFactoryClassLoader = logFactoryClass.getClassLoader();
<a name="1297" href="#1297">1297</a>                 <strong class="jxr_keyword">if</strong> (logFactoryClassLoader == <strong class="jxr_keyword">null</strong>) {
<a name="1298" href="#1298">1298</a>                     logDiagnostic(<span class="jxr_string">"[CUSTOM LOG FACTORY] was loaded by the boot classloader"</span>);
<a name="1299" href="#1299">1299</a>                 } <strong class="jxr_keyword">else</strong> {
<a name="1300" href="#1300">1300</a>                     logHierarchy(<span class="jxr_string">"[CUSTOM LOG FACTORY] "</span>, logFactoryClassLoader);
<a name="1301" href="#1301">1301</a>                     Class factoryFromCustomLoader
<a name="1302" href="#1302">1302</a>                         = Class.forName(<span class="jxr_string">"org.apache.commons.logging.LogFactory"</span>, false, logFactoryClassLoader);
<a name="1303" href="#1303">1303</a>                     implementsLogFactory = factoryFromCustomLoader.isAssignableFrom(logFactoryClass);
<a name="1304" href="#1304">1304</a>                     <strong class="jxr_keyword">if</strong> (implementsLogFactory) {
<a name="1305" href="#1305">1305</a>                         logDiagnostic(<span class="jxr_string">"[CUSTOM LOG FACTORY] "</span> + logFactoryClass.getName()
<a name="1306" href="#1306">1306</a>                                 + <span class="jxr_string">" implements LogFactory but was loaded by an incompatible classloader."</span>);
<a name="1307" href="#1307">1307</a>                     } <strong class="jxr_keyword">else</strong> {
<a name="1308" href="#1308">1308</a>                         logDiagnostic(<span class="jxr_string">"[CUSTOM LOG FACTORY] "</span> + logFactoryClass.getName()
<a name="1309" href="#1309">1309</a>                                 + <span class="jxr_string">" does not implement LogFactory."</span>);
<a name="1310" href="#1310">1310</a>                     }
<a name="1311" href="#1311">1311</a>                 }
<a name="1312" href="#1312">1312</a>             } <strong class="jxr_keyword">catch</strong> (SecurityException e) {
<a name="1313" href="#1313">1313</a>                 <em class="jxr_comment">//</em>
<a name="1314" href="#1314">1314</a>                 <em class="jxr_comment">// The application is running within a hostile security environment.</em>
<a name="1315" href="#1315">1315</a>                 <em class="jxr_comment">// This will make it very hard to diagnose issues with JCL.</em>
<a name="1316" href="#1316">1316</a>                 <em class="jxr_comment">// Consider running less securely whilst debugging this issue.</em>
<a name="1317" href="#1317">1317</a>                 <em class="jxr_comment">//</em>
<a name="1318" href="#1318">1318</a>                 logDiagnostic(<span class="jxr_string">"[CUSTOM LOG FACTORY] SecurityException thrown whilst trying to determine whether "</span> +
<a name="1319" href="#1319">1319</a>                         <span class="jxr_string">"the compatibility was caused by a classloader conflict: "</span>
<a name="1320" href="#1320">1320</a>                         + e.getMessage());
<a name="1321" href="#1321">1321</a>             } <strong class="jxr_keyword">catch</strong> (LinkageError e) {
<a name="1322" href="#1322">1322</a>                 <em class="jxr_comment">//</em>
<a name="1323" href="#1323">1323</a>                 <em class="jxr_comment">// This should be an unusual circumstance.</em>
<a name="1324" href="#1324">1324</a>                 <em class="jxr_comment">// LinkageError's usually indicate that a dependent class has incompatibly changed.</em>
<a name="1325" href="#1325">1325</a>                 <em class="jxr_comment">// Another possibility may be an exception thrown by an initializer.</em>
<a name="1326" href="#1326">1326</a>                 <em class="jxr_comment">// Time for a clean rebuild?</em>
<a name="1327" href="#1327">1327</a>                 <em class="jxr_comment">//</em>
<a name="1328" href="#1328">1328</a>                 logDiagnostic(<span class="jxr_string">"[CUSTOM LOG FACTORY] LinkageError thrown whilst trying to determine whether "</span> +
<a name="1329" href="#1329">1329</a>                         <span class="jxr_string">"the compatibility was caused by a classloader conflict: "</span>
<a name="1330" href="#1330">1330</a>                         + e.getMessage());
<a name="1331" href="#1331">1331</a>             } <strong class="jxr_keyword">catch</strong> (ClassNotFoundException e) {
<a name="1332" href="#1332">1332</a>                 <em class="jxr_comment">//</em>
<a name="1333" href="#1333">1333</a>                 <em class="jxr_comment">// LogFactory cannot be loaded by the classloader which loaded the custom factory implementation.</em>
<a name="1334" href="#1334">1334</a>                 <em class="jxr_comment">// The custom implementation is not viable until this is corrected.</em>
<a name="1335" href="#1335">1335</a>                 <em class="jxr_comment">// Ensure that the JCL jar and the custom class are available from the same classloader.</em>
<a name="1336" href="#1336">1336</a>                 <em class="jxr_comment">// Running with diagnostics on should give information about the classloaders used</em>
<a name="1337" href="#1337">1337</a>                 <em class="jxr_comment">// to load the custom factory.</em>
<a name="1338" href="#1338">1338</a>                 <em class="jxr_comment">//</em>
<a name="1339" href="#1339">1339</a>                 logDiagnostic(<span class="jxr_string">"[CUSTOM LOG FACTORY] LogFactory class cannot be loaded by classloader which loaded the "</span> +
<a name="1340" href="#1340">1340</a>                         <span class="jxr_string">"custom LogFactory implementation. Is the custom factory in the right classloader?"</span>);
<a name="1341" href="#1341">1341</a>             }
<a name="1342" href="#1342">1342</a>         }
<a name="1343" href="#1343">1343</a>         <strong class="jxr_keyword">return</strong> implementsLogFactory;
<a name="1344" href="#1344">1344</a>     }
<a name="1345" href="#1345">1345</a> 
<a name="1346" href="#1346">1346</a>     <em class="jxr_javadoccomment">/**</em>
<a name="1347" href="#1347">1347</a> <em class="jxr_javadoccomment">     * Applets may run in an environment where accessing resources of a loader is</em>
<a name="1348" href="#1348">1348</a> <em class="jxr_javadoccomment">     * a secure operation, but where the commons-logging library has explicitly</em>
<a name="1349" href="#1349">1349</a> <em class="jxr_javadoccomment">     * been granted permission for that operation. In this case, we need to </em>
<a name="1350" href="#1350">1350</a> <em class="jxr_javadoccomment">     * run the operation using an AccessController.</em>
<a name="1351" href="#1351">1351</a> <em class="jxr_javadoccomment">     */</em>
<a name="1352" href="#1352">1352</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> InputStream getResourceAsStream(<strong class="jxr_keyword">final</strong> ClassLoader loader,
<a name="1353" href="#1353">1353</a>                                                    <strong class="jxr_keyword">final</strong> String name)
<a name="1354" href="#1354">1354</a>     {
<a name="1355" href="#1355">1355</a>         <strong class="jxr_keyword">return</strong> (InputStream)AccessController.doPrivileged(
<a name="1356" href="#1356">1356</a>             <strong class="jxr_keyword">new</strong> PrivilegedAction() {
<a name="1357" href="#1357">1357</a>                 <strong class="jxr_keyword">public</strong> Object run() {
<a name="1358" href="#1358">1358</a>                     <strong class="jxr_keyword">if</strong> (loader != <strong class="jxr_keyword">null</strong>) {
<a name="1359" href="#1359">1359</a>                         <strong class="jxr_keyword">return</strong> loader.getResourceAsStream(name);
<a name="1360" href="#1360">1360</a>                     } <strong class="jxr_keyword">else</strong> {
<a name="1361" href="#1361">1361</a>                         <strong class="jxr_keyword">return</strong> ClassLoader.getSystemResourceAsStream(name);
<a name="1362" href="#1362">1362</a>                     }
<a name="1363" href="#1363">1363</a>                 }
<a name="1364" href="#1364">1364</a>             });
<a name="1365" href="#1365">1365</a>     }
<a name="1366" href="#1366">1366</a> 
<a name="1367" href="#1367">1367</a>     <em class="jxr_javadoccomment">/**</em>
<a name="1368" href="#1368">1368</a> <em class="jxr_javadoccomment">     * Given a filename, return an enumeration of URLs pointing to</em>
<a name="1369" href="#1369">1369</a> <em class="jxr_javadoccomment">     * all the occurrences of that filename in the classpath.</em>
<a name="1370" href="#1370">1370</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="1371" href="#1371">1371</a> <em class="jxr_javadoccomment">     * This is just like ClassLoader.getResources except that the</em>
<a name="1372" href="#1372">1372</a> <em class="jxr_javadoccomment">     * operation is done under an AccessController so that this method will</em>
<a name="1373" href="#1373">1373</a> <em class="jxr_javadoccomment">     * succeed when this jarfile is privileged but the caller is not.</em>
<a name="1374" href="#1374">1374</a> <em class="jxr_javadoccomment">     * This method must therefore remain private to avoid security issues.</em>
<a name="1375" href="#1375">1375</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="1376" href="#1376">1376</a> <em class="jxr_javadoccomment">     * If no instances are found, an Enumeration is returned whose</em>
<a name="1377" href="#1377">1377</a> <em class="jxr_javadoccomment">     * hasMoreElements method returns false (ie an "empty" enumeration).</em>
<a name="1378" href="#1378">1378</a> <em class="jxr_javadoccomment">     * If resources could not be listed for some reason, null is returned.</em>
<a name="1379" href="#1379">1379</a> <em class="jxr_javadoccomment">     */</em>
<a name="1380" href="#1380">1380</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> Enumeration getResources(<strong class="jxr_keyword">final</strong> ClassLoader loader,
<a name="1381" href="#1381">1381</a>             <strong class="jxr_keyword">final</strong> String name)
<a name="1382" href="#1382">1382</a>     {
<a name="1383" href="#1383">1383</a>         PrivilegedAction action = 
<a name="1384" href="#1384">1384</a>             <strong class="jxr_keyword">new</strong> PrivilegedAction() {
<a name="1385" href="#1385">1385</a>                 <strong class="jxr_keyword">public</strong> Object run() {
<a name="1386" href="#1386">1386</a>                     <strong class="jxr_keyword">try</strong> {
<a name="1387" href="#1387">1387</a>                         <strong class="jxr_keyword">if</strong> (loader != <strong class="jxr_keyword">null</strong>) {
<a name="1388" href="#1388">1388</a>                             <strong class="jxr_keyword">return</strong> loader.getResources(name);
<a name="1389" href="#1389">1389</a>                         } <strong class="jxr_keyword">else</strong> {
<a name="1390" href="#1390">1390</a>                             <strong class="jxr_keyword">return</strong> ClassLoader.getSystemResources(name);
<a name="1391" href="#1391">1391</a>                         }
<a name="1392" href="#1392">1392</a>                     } <strong class="jxr_keyword">catch</strong>(IOException e) {
<a name="1393" href="#1393">1393</a>                         <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="1394" href="#1394">1394</a>                             logDiagnostic(
<a name="1395" href="#1395">1395</a>                                 <span class="jxr_string">"Exception while trying to find configuration file "</span>
<a name="1396" href="#1396">1396</a>                                 + name + <span class="jxr_string">":"</span> + e.getMessage());
<a name="1397" href="#1397">1397</a>                         }
<a name="1398" href="#1398">1398</a>                         <strong class="jxr_keyword">return</strong> <strong class="jxr_keyword">null</strong>;
<a name="1399" href="#1399">1399</a>                     } <strong class="jxr_keyword">catch</strong>(NoSuchMethodError e) {
<a name="1400" href="#1400">1400</a>                         <em class="jxr_comment">// we must be running on a 1.1 JVM which doesn't support</em>
<a name="1401" href="#1401">1401</a>                         <em class="jxr_comment">// ClassLoader.getSystemResources; just return null in</em>
<a name="1402" href="#1402">1402</a>                         <em class="jxr_comment">// this case.</em>
<a name="1403" href="#1403">1403</a>                         <strong class="jxr_keyword">return</strong> <strong class="jxr_keyword">null</strong>;
<a name="1404" href="#1404">1404</a>                     }
<a name="1405" href="#1405">1405</a>                 }
<a name="1406" href="#1406">1406</a>             };
<a name="1407" href="#1407">1407</a>         Object result = AccessController.doPrivileged(action);
<a name="1408" href="#1408">1408</a>         <strong class="jxr_keyword">return</strong> (Enumeration) result;
<a name="1409" href="#1409">1409</a>     }
<a name="1410" href="#1410">1410</a> 
<a name="1411" href="#1411">1411</a>     <em class="jxr_javadoccomment">/**</em>
<a name="1412" href="#1412">1412</a> <em class="jxr_javadoccomment">     * Given a URL that refers to a .properties file, load that file.</em>
<a name="1413" href="#1413">1413</a> <em class="jxr_javadoccomment">     * This is done under an AccessController so that this method will</em>
<a name="1414" href="#1414">1414</a> <em class="jxr_javadoccomment">     * succeed when this jarfile is privileged but the caller is not.</em>
<a name="1415" href="#1415">1415</a> <em class="jxr_javadoccomment">     * This method must therefore remain private to avoid security issues.</em>
<a name="1416" href="#1416">1416</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="1417" href="#1417">1417</a> <em class="jxr_javadoccomment">     * Null is returned if the URL cannot be opened.</em>
<a name="1418" href="#1418">1418</a> <em class="jxr_javadoccomment">     */</em>
<a name="1419" href="#1419">1419</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> Properties getProperties(<strong class="jxr_keyword">final</strong> URL url) {
<a name="1420" href="#1420">1420</a>         PrivilegedAction action = 
<a name="1421" href="#1421">1421</a>             <strong class="jxr_keyword">new</strong> PrivilegedAction() {
<a name="1422" href="#1422">1422</a>                 <strong class="jxr_keyword">public</strong> Object run() {
<a name="1423" href="#1423">1423</a>                     <strong class="jxr_keyword">try</strong> {
<a name="1424" href="#1424">1424</a>                         InputStream stream = url.openStream();
<a name="1425" href="#1425">1425</a>                         <strong class="jxr_keyword">if</strong> (stream != <strong class="jxr_keyword">null</strong>) {
<a name="1426" href="#1426">1426</a>                             Properties props = <strong class="jxr_keyword">new</strong> Properties();
<a name="1427" href="#1427">1427</a>                             props.load(stream);
<a name="1428" href="#1428">1428</a>                             stream.close();
<a name="1429" href="#1429">1429</a>                             <strong class="jxr_keyword">return</strong> props;
<a name="1430" href="#1430">1430</a>                         }
<a name="1431" href="#1431">1431</a>                     } <strong class="jxr_keyword">catch</strong>(IOException e) {
<a name="1432" href="#1432">1432</a>                         <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="1433" href="#1433">1433</a>                             logDiagnostic(<span class="jxr_string">"Unable to read URL "</span> + url);
<a name="1434" href="#1434">1434</a>                         }
<a name="1435" href="#1435">1435</a>                     }
<a name="1436" href="#1436">1436</a> 
<a name="1437" href="#1437">1437</a>                     <strong class="jxr_keyword">return</strong> <strong class="jxr_keyword">null</strong>;
<a name="1438" href="#1438">1438</a>                 }
<a name="1439" href="#1439">1439</a>             };
<a name="1440" href="#1440">1440</a>         <strong class="jxr_keyword">return</strong> (Properties) AccessController.doPrivileged(action);
<a name="1441" href="#1441">1441</a>     }
<a name="1442" href="#1442">1442</a> 
<a name="1443" href="#1443">1443</a>     <em class="jxr_javadoccomment">/**</em>
<a name="1444" href="#1444">1444</a> <em class="jxr_javadoccomment">     * Locate a user-provided configuration file.</em>
<a name="1445" href="#1445">1445</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="1446" href="#1446">1446</a> <em class="jxr_javadoccomment">     * The classpath of the specified classLoader (usually the context classloader)</em>
<a name="1447" href="#1447">1447</a> <em class="jxr_javadoccomment">     * is searched for properties files of the specified name. If none is found,</em>
<a name="1448" href="#1448">1448</a> <em class="jxr_javadoccomment">     * null is returned. If more than one is found, then the file with the greatest</em>
<a name="1449" href="#1449">1449</a> <em class="jxr_javadoccomment">     * value for its PRIORITY property is returned. If multiple files have the</em>
<a name="1450" href="#1450">1450</a> <em class="jxr_javadoccomment">     * same PRIORITY value then the first in the classpath is returned.</em>
<a name="1451" href="#1451">1451</a> <em class="jxr_javadoccomment">     * &lt;p&gt; </em>
<a name="1452" href="#1452">1452</a> <em class="jxr_javadoccomment">     * This differs from the 1.0.x releases; those always use the first one found.</em>
<a name="1453" href="#1453">1453</a> <em class="jxr_javadoccomment">     * However as the priority is a new field, this change is backwards compatible.</em>
<a name="1454" href="#1454">1454</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="1455" href="#1455">1455</a> <em class="jxr_javadoccomment">     * The purpose of the priority field is to allow a webserver administrator to</em>
<a name="1456" href="#1456">1456</a> <em class="jxr_javadoccomment">     * override logging settings in all webapps by placing a commons-logging.properties</em>
<a name="1457" href="#1457">1457</a> <em class="jxr_javadoccomment">     * file in a shared classpath location with a priority &gt; 0; this overrides any</em>
<a name="1458" href="#1458">1458</a> <em class="jxr_javadoccomment">     * commons-logging.properties files without priorities which are in the</em>
<a name="1459" href="#1459">1459</a> <em class="jxr_javadoccomment">     * webapps. Webapps can also use explicit priorities to override a configuration</em>
<a name="1460" href="#1460">1460</a> <em class="jxr_javadoccomment">     * file in the shared classpath if needed. </em>
<a name="1461" href="#1461">1461</a> <em class="jxr_javadoccomment">     */</em>
<a name="1462" href="#1462">1462</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> Properties getConfigurationFile(
<a name="1463" href="#1463">1463</a>             ClassLoader classLoader, String fileName) {
<a name="1464" href="#1464">1464</a> 
<a name="1465" href="#1465">1465</a>         Properties props = <strong class="jxr_keyword">null</strong>;
<a name="1466" href="#1466">1466</a>         <strong class="jxr_keyword">double</strong> priority = 0.0;
<a name="1467" href="#1467">1467</a>         URL propsUrl = <strong class="jxr_keyword">null</strong>;
<a name="1468" href="#1468">1468</a>         <strong class="jxr_keyword">try</strong> {
<a name="1469" href="#1469">1469</a>             Enumeration urls = getResources(classLoader, fileName);
<a name="1470" href="#1470">1470</a> 
<a name="1471" href="#1471">1471</a>             <strong class="jxr_keyword">if</strong> (urls == <strong class="jxr_keyword">null</strong>) {
<a name="1472" href="#1472">1472</a>                 <strong class="jxr_keyword">return</strong> <strong class="jxr_keyword">null</strong>;
<a name="1473" href="#1473">1473</a>             }
<a name="1474" href="#1474">1474</a>             
<a name="1475" href="#1475">1475</a>             <strong class="jxr_keyword">while</strong> (urls.hasMoreElements()) {
<a name="1476" href="#1476">1476</a>                 URL url = (URL) urls.nextElement();
<a name="1477" href="#1477">1477</a>                 
<a name="1478" href="#1478">1478</a>                 Properties newProps = getProperties(url);
<a name="1479" href="#1479">1479</a>                 <strong class="jxr_keyword">if</strong> (newProps != <strong class="jxr_keyword">null</strong>) {
<a name="1480" href="#1480">1480</a>                     <strong class="jxr_keyword">if</strong> (props == <strong class="jxr_keyword">null</strong>) {
<a name="1481" href="#1481">1481</a>                         propsUrl = url; 
<a name="1482" href="#1482">1482</a>                         props = newProps;
<a name="1483" href="#1483">1483</a>                         String priorityStr = props.getProperty(PRIORITY_KEY);
<a name="1484" href="#1484">1484</a>                         priority = 0.0;
<a name="1485" href="#1485">1485</a>                         <strong class="jxr_keyword">if</strong> (priorityStr != <strong class="jxr_keyword">null</strong>) {
<a name="1486" href="#1486">1486</a>                             priority = Double.parseDouble(priorityStr);
<a name="1487" href="#1487">1487</a>                         }
<a name="1488" href="#1488">1488</a> 
<a name="1489" href="#1489">1489</a>                         <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="1490" href="#1490">1490</a>                             logDiagnostic(
<a name="1491" href="#1491">1491</a>                                 <span class="jxr_string">"[LOOKUP] Properties file found at '"</span> + url + <span class="jxr_string">"'"</span>
<a name="1492" href="#1492">1492</a>                                 + <span class="jxr_string">" with priority "</span> + priority); 
<a name="1493" href="#1493">1493</a>                         }
<a name="1494" href="#1494">1494</a>                     } <strong class="jxr_keyword">else</strong> {
<a name="1495" href="#1495">1495</a>                         String newPriorityStr = newProps.getProperty(PRIORITY_KEY);
<a name="1496" href="#1496">1496</a>                         <strong class="jxr_keyword">double</strong> newPriority = 0.0;
<a name="1497" href="#1497">1497</a>                         <strong class="jxr_keyword">if</strong> (newPriorityStr != <strong class="jxr_keyword">null</strong>) {
<a name="1498" href="#1498">1498</a>                             newPriority = Double.parseDouble(newPriorityStr);
<a name="1499" href="#1499">1499</a>                         }
<a name="1500" href="#1500">1500</a> 
<a name="1501" href="#1501">1501</a>                         <strong class="jxr_keyword">if</strong> (newPriority &gt; priority) {
<a name="1502" href="#1502">1502</a>                             <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="1503" href="#1503">1503</a>                                 logDiagnostic(
<a name="1504" href="#1504">1504</a>                                     <span class="jxr_string">"[LOOKUP] Properties file at '"</span> + url + <span class="jxr_string">"'"</span>
<a name="1505" href="#1505">1505</a>                                     + <span class="jxr_string">" with priority "</span> + newPriority 
<a name="1506" href="#1506">1506</a>                                     + <span class="jxr_string">" overrides file at '"</span> + propsUrl + <span class="jxr_string">"'"</span>
<a name="1507" href="#1507">1507</a>                                     + <span class="jxr_string">" with priority "</span> + priority);
<a name="1508" href="#1508">1508</a>                             }
<a name="1509" href="#1509">1509</a> 
<a name="1510" href="#1510">1510</a>                             propsUrl = url; 
<a name="1511" href="#1511">1511</a>                             props = newProps;
<a name="1512" href="#1512">1512</a>                             priority = newPriority;
<a name="1513" href="#1513">1513</a>                         } <strong class="jxr_keyword">else</strong> {
<a name="1514" href="#1514">1514</a>                             <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="1515" href="#1515">1515</a>                                 logDiagnostic(
<a name="1516" href="#1516">1516</a>                                     <span class="jxr_string">"[LOOKUP] Properties file at '"</span> + url + <span class="jxr_string">"'"</span>
<a name="1517" href="#1517">1517</a>                                     + <span class="jxr_string">" with priority "</span> + newPriority 
<a name="1518" href="#1518">1518</a>                                     + <span class="jxr_string">" does not override file at '"</span> + propsUrl + <span class="jxr_string">"'"</span>
<a name="1519" href="#1519">1519</a>                                     + <span class="jxr_string">" with priority "</span> + priority);
<a name="1520" href="#1520">1520</a>                             }
<a name="1521" href="#1521">1521</a>                         }
<a name="1522" href="#1522">1522</a>                     }
<a name="1523" href="#1523">1523</a> 
<a name="1524" href="#1524">1524</a>                 }
<a name="1525" href="#1525">1525</a>             }
<a name="1526" href="#1526">1526</a>         } <strong class="jxr_keyword">catch</strong> (SecurityException e) {
<a name="1527" href="#1527">1527</a>             <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="1528" href="#1528">1528</a>                 logDiagnostic(<span class="jxr_string">"SecurityException thrown while trying to find/read config files."</span>);
<a name="1529" href="#1529">1529</a>             }
<a name="1530" href="#1530">1530</a>         }
<a name="1531" href="#1531">1531</a> 
<a name="1532" href="#1532">1532</a>         <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="1533" href="#1533">1533</a>             <strong class="jxr_keyword">if</strong> (props == <strong class="jxr_keyword">null</strong>) {
<a name="1534" href="#1534">1534</a>                 logDiagnostic(
<a name="1535" href="#1535">1535</a>                     <span class="jxr_string">"[LOOKUP] No properties file of name '"</span> + fileName
<a name="1536" href="#1536">1536</a>                     + <span class="jxr_string">"' found."</span>);
<a name="1537" href="#1537">1537</a>             } <strong class="jxr_keyword">else</strong> {
<a name="1538" href="#1538">1538</a>                 logDiagnostic(
<a name="1539" href="#1539">1539</a>                     <span class="jxr_string">"[LOOKUP] Properties file of name '"</span> + fileName
<a name="1540" href="#1540">1540</a>                     + <span class="jxr_string">"' found at '"</span> + propsUrl + '&quot;');
<a name="1541" href="#1541">1541</a>             }
<a name="1542" href="#1542">1542</a>         }
<a name="1543" href="#1543">1543</a> 
<a name="1544" href="#1544">1544</a>         <strong class="jxr_keyword">return</strong> props;
<a name="1545" href="#1545">1545</a>     }
<a name="1546" href="#1546">1546</a> 
<a name="1547" href="#1547">1547</a>     <em class="jxr_javadoccomment">/**</em>
<a name="1548" href="#1548">1548</a> <em class="jxr_javadoccomment">     * Read the specified system property, using an AccessController so that </em>
<a name="1549" href="#1549">1549</a> <em class="jxr_javadoccomment">     * the property can be read if JCL has been granted the appropriate</em>
<a name="1550" href="#1550">1550</a> <em class="jxr_javadoccomment">     * security rights even if the calling code has not.</em>
<a name="1551" href="#1551">1551</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="1552" href="#1552">1552</a> <em class="jxr_javadoccomment">     * Take care not to expose the value returned by this method to the</em>
<a name="1553" href="#1553">1553</a> <em class="jxr_javadoccomment">     * calling application in any way; otherwise the calling app can use that</em>
<a name="1554" href="#1554">1554</a> <em class="jxr_javadoccomment">     * info to access data that should not be available to it.</em>
<a name="1555" href="#1555">1555</a> <em class="jxr_javadoccomment">     */</em>
<a name="1556" href="#1556">1556</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> String getSystemProperty(<strong class="jxr_keyword">final</strong> String key, <strong class="jxr_keyword">final</strong> String def)
<a name="1557" href="#1557">1557</a>     <strong class="jxr_keyword">throws</strong> SecurityException {
<a name="1558" href="#1558">1558</a>         <strong class="jxr_keyword">return</strong> (String) AccessController.doPrivileged(
<a name="1559" href="#1559">1559</a>                 <strong class="jxr_keyword">new</strong> PrivilegedAction() {
<a name="1560" href="#1560">1560</a>                     <strong class="jxr_keyword">public</strong> Object run() {
<a name="1561" href="#1561">1561</a>                         <strong class="jxr_keyword">return</strong> System.getProperty(key, def);
<a name="1562" href="#1562">1562</a>                     }
<a name="1563" href="#1563">1563</a>                 });
<a name="1564" href="#1564">1564</a>     }
<a name="1565" href="#1565">1565</a> 
<a name="1566" href="#1566">1566</a>     <em class="jxr_javadoccomment">/**</em>
<a name="1567" href="#1567">1567</a> <em class="jxr_javadoccomment">     * Determines whether the user wants internal diagnostic output. If so,</em>
<a name="1568" href="#1568">1568</a> <em class="jxr_javadoccomment">     * returns an appropriate writer object. Users can enable diagnostic</em>
<a name="1569" href="#1569">1569</a> <em class="jxr_javadoccomment">     * output by setting the system property named {@link #DIAGNOSTICS_DEST_PROPERTY} to</em>
<a name="1570" href="#1570">1570</a> <em class="jxr_javadoccomment">     * a filename, or the special values STDOUT or STDERR. </em>
<a name="1571" href="#1571">1571</a> <em class="jxr_javadoccomment">     */</em>
<a name="1572" href="#1572">1572</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">void</strong> initDiagnostics() {
<a name="1573" href="#1573">1573</a>         String dest;
<a name="1574" href="#1574">1574</a>         <strong class="jxr_keyword">try</strong> {
<a name="1575" href="#1575">1575</a>             dest = getSystemProperty(DIAGNOSTICS_DEST_PROPERTY, <strong class="jxr_keyword">null</strong>);
<a name="1576" href="#1576">1576</a>             <strong class="jxr_keyword">if</strong> (dest == <strong class="jxr_keyword">null</strong>) {
<a name="1577" href="#1577">1577</a>                 <strong class="jxr_keyword">return</strong>;
<a name="1578" href="#1578">1578</a>             }
<a name="1579" href="#1579">1579</a>         } <strong class="jxr_keyword">catch</strong>(SecurityException ex) {
<a name="1580" href="#1580">1580</a>             <em class="jxr_comment">// We must be running in some very secure environment.</em>
<a name="1581" href="#1581">1581</a>             <em class="jxr_comment">// We just have to assume output is not wanted..</em>
<a name="1582" href="#1582">1582</a>             <strong class="jxr_keyword">return</strong>;
<a name="1583" href="#1583">1583</a>         }
<a name="1584" href="#1584">1584</a> 
<a name="1585" href="#1585">1585</a>         <strong class="jxr_keyword">if</strong> (dest.equals(<span class="jxr_string">"STDOUT"</span>)) {
<a name="1586" href="#1586">1586</a>             diagnosticsStream = System.out;
<a name="1587" href="#1587">1587</a>         } <strong class="jxr_keyword">else</strong> <strong class="jxr_keyword">if</strong> (dest.equals(<span class="jxr_string">"STDERR"</span>)) {
<a name="1588" href="#1588">1588</a>             diagnosticsStream = System.err;
<a name="1589" href="#1589">1589</a>         } <strong class="jxr_keyword">else</strong> {
<a name="1590" href="#1590">1590</a>             <strong class="jxr_keyword">try</strong> {
<a name="1591" href="#1591">1591</a>                 <em class="jxr_comment">// open the file in append mode</em>
<a name="1592" href="#1592">1592</a>                 FileOutputStream fos = <strong class="jxr_keyword">new</strong> FileOutputStream(dest, <strong class="jxr_keyword">true</strong>);
<a name="1593" href="#1593">1593</a>                 diagnosticsStream = <strong class="jxr_keyword">new</strong> PrintStream(fos);
<a name="1594" href="#1594">1594</a>             } <strong class="jxr_keyword">catch</strong>(IOException ex) {
<a name="1595" href="#1595">1595</a>                 <em class="jxr_comment">// We should report this to the user - but how?</em>
<a name="1596" href="#1596">1596</a>                 <strong class="jxr_keyword">return</strong>;
<a name="1597" href="#1597">1597</a>             }
<a name="1598" href="#1598">1598</a>         }
<a name="1599" href="#1599">1599</a> 
<a name="1600" href="#1600">1600</a>         <em class="jxr_comment">// In order to avoid confusion where multiple instances of JCL are</em>
<a name="1601" href="#1601">1601</a>         <em class="jxr_comment">// being used via different classloaders within the same app, we</em>
<a name="1602" href="#1602">1602</a>         <em class="jxr_comment">// ensure each logged message has a prefix of form</em>
<a name="1603" href="#1603">1603</a>         <em class="jxr_comment">// [LogFactory from classloader OID]</em>
<a name="1604" href="#1604">1604</a>         <em class="jxr_comment">//</em>
<a name="1605" href="#1605">1605</a>         <em class="jxr_comment">// Note that this prefix should be kept consistent with that </em>
<a name="1606" href="#1606">1606</a>         <em class="jxr_comment">// in LogFactoryImpl. However here we don't need to output info</em>
<a name="1607" href="#1607">1607</a>         <em class="jxr_comment">// about the actual *instance* of LogFactory, as all methods that</em>
<a name="1608" href="#1608">1608</a>         <em class="jxr_comment">// output diagnostics from this class are static.</em>
<a name="1609" href="#1609">1609</a>         String classLoaderName;
<a name="1610" href="#1610">1610</a>         <strong class="jxr_keyword">try</strong> {
<a name="1611" href="#1611">1611</a>             ClassLoader classLoader = thisClassLoader;
<a name="1612" href="#1612">1612</a>             <strong class="jxr_keyword">if</strong> (thisClassLoader == <strong class="jxr_keyword">null</strong>) {
<a name="1613" href="#1613">1613</a>                 classLoaderName = <span class="jxr_string">"BOOTLOADER"</span>;
<a name="1614" href="#1614">1614</a>             } <strong class="jxr_keyword">else</strong> {
<a name="1615" href="#1615">1615</a>                 classLoaderName = objectId(classLoader);
<a name="1616" href="#1616">1616</a>             }
<a name="1617" href="#1617">1617</a>         } <strong class="jxr_keyword">catch</strong>(SecurityException e) {
<a name="1618" href="#1618">1618</a>             classLoaderName = <span class="jxr_string">"UNKNOWN"</span>;
<a name="1619" href="#1619">1619</a>         }
<a name="1620" href="#1620">1620</a>         diagnosticPrefix = <span class="jxr_string">"[LogFactory from "</span> + classLoaderName + <span class="jxr_string">"] "</span>;
<a name="1621" href="#1621">1621</a>     }
<a name="1622" href="#1622">1622</a> 
<a name="1623" href="#1623">1623</a>     <em class="jxr_javadoccomment">/**</em>
<a name="1624" href="#1624">1624</a> <em class="jxr_javadoccomment">     * Indicates true if the user has enabled internal logging.</em>
<a name="1625" href="#1625">1625</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="1626" href="#1626">1626</a> <em class="jxr_javadoccomment">     * By the way, sorry for the incorrect grammar, but calling this method</em>
<a name="1627" href="#1627">1627</a> <em class="jxr_javadoccomment">     * areDiagnosticsEnabled just isn't java beans style.</em>
<a name="1628" href="#1628">1628</a> <em class="jxr_javadoccomment">     * </em>
<a name="1629" href="#1629">1629</a> <em class="jxr_javadoccomment">     * @return true if calls to logDiagnostic will have any effect.</em>
<a name="1630" href="#1630">1630</a> <em class="jxr_javadoccomment">     * @since 1.1</em>
<a name="1631" href="#1631">1631</a> <em class="jxr_javadoccomment">     */</em>
<a name="1632" href="#1632">1632</a>     <strong class="jxr_keyword">protected</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">boolean</strong> isDiagnosticsEnabled() {
<a name="1633" href="#1633">1633</a>         <strong class="jxr_keyword">return</strong> diagnosticsStream != <strong class="jxr_keyword">null</strong>;
<a name="1634" href="#1634">1634</a>     }
<a name="1635" href="#1635">1635</a> 
<a name="1636" href="#1636">1636</a>     <em class="jxr_javadoccomment">/**</em>
<a name="1637" href="#1637">1637</a> <em class="jxr_javadoccomment">     * Write the specified message to the internal logging destination.</em>
<a name="1638" href="#1638">1638</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="1639" href="#1639">1639</a> <em class="jxr_javadoccomment">     * Note that this method is private; concrete subclasses of this class</em>
<a name="1640" href="#1640">1640</a> <em class="jxr_javadoccomment">     * should not call it because the diagnosticPrefix string this</em>
<a name="1641" href="#1641">1641</a> <em class="jxr_javadoccomment">     * method puts in front of all its messages is LogFactory@....,</em>
<a name="1642" href="#1642">1642</a> <em class="jxr_javadoccomment">     * while subclasses should put SomeSubClass@...</em>
<a name="1643" href="#1643">1643</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="1644" href="#1644">1644</a> <em class="jxr_javadoccomment">     * Subclasses should instead compute their own prefix, then call</em>
<a name="1645" href="#1645">1645</a> <em class="jxr_javadoccomment">     * logRawDiagnostic. Note that calling isDiagnosticsEnabled is</em>
<a name="1646" href="#1646">1646</a> <em class="jxr_javadoccomment">     * fine for subclasses.</em>
<a name="1647" href="#1647">1647</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="1648" href="#1648">1648</a> <em class="jxr_javadoccomment">     * Note that it is safe to call this method before initDiagnostics</em>
<a name="1649" href="#1649">1649</a> <em class="jxr_javadoccomment">     * is called; any output will just be ignored (as isDiagnosticsEnabled</em>
<a name="1650" href="#1650">1650</a> <em class="jxr_javadoccomment">     * will return false).</em>
<a name="1651" href="#1651">1651</a> <em class="jxr_javadoccomment">     * </em>
<a name="1652" href="#1652">1652</a> <em class="jxr_javadoccomment">     * @param msg is the diagnostic message to be output.</em>
<a name="1653" href="#1653">1653</a> <em class="jxr_javadoccomment">     */</em>
<a name="1654" href="#1654">1654</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">void</strong> logDiagnostic(String msg) {
<a name="1655" href="#1655">1655</a>         <strong class="jxr_keyword">if</strong> (diagnosticsStream != <strong class="jxr_keyword">null</strong>) {
<a name="1656" href="#1656">1656</a>             diagnosticsStream.print(diagnosticPrefix);
<a name="1657" href="#1657">1657</a>             diagnosticsStream.println(msg);
<a name="1658" href="#1658">1658</a>             diagnosticsStream.flush();
<a name="1659" href="#1659">1659</a>         }
<a name="1660" href="#1660">1660</a>     }
<a name="1661" href="#1661">1661</a> 
<a name="1662" href="#1662">1662</a>     <em class="jxr_javadoccomment">/**</em>
<a name="1663" href="#1663">1663</a> <em class="jxr_javadoccomment">     * Write the specified message to the internal logging destination.</em>
<a name="1664" href="#1664">1664</a> <em class="jxr_javadoccomment">     * </em>
<a name="1665" href="#1665">1665</a> <em class="jxr_javadoccomment">     * @param msg is the diagnostic message to be output.</em>
<a name="1666" href="#1666">1666</a> <em class="jxr_javadoccomment">     * @since 1.1</em>
<a name="1667" href="#1667">1667</a> <em class="jxr_javadoccomment">     */</em>
<a name="1668" href="#1668">1668</a>     <strong class="jxr_keyword">protected</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">void</strong> logRawDiagnostic(String msg) {
<a name="1669" href="#1669">1669</a>         <strong class="jxr_keyword">if</strong> (diagnosticsStream != <strong class="jxr_keyword">null</strong>) {
<a name="1670" href="#1670">1670</a>             diagnosticsStream.println(msg);
<a name="1671" href="#1671">1671</a>             diagnosticsStream.flush();
<a name="1672" href="#1672">1672</a>         }
<a name="1673" href="#1673">1673</a>     }
<a name="1674" href="#1674">1674</a> 
<a name="1675" href="#1675">1675</a>     <em class="jxr_javadoccomment">/**</em>
<a name="1676" href="#1676">1676</a> <em class="jxr_javadoccomment">     * Generate useful diagnostics regarding the classloader tree for</em>
<a name="1677" href="#1677">1677</a> <em class="jxr_javadoccomment">     * the specified class.</em>
<a name="1678" href="#1678">1678</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="1679" href="#1679">1679</a> <em class="jxr_javadoccomment">     * As an example, if the specified class was loaded via a webapp's</em>
<a name="1680" href="#1680">1680</a> <em class="jxr_javadoccomment">     * classloader, then you may get the following output:</em>
<a name="1681" href="#1681">1681</a> <em class="jxr_javadoccomment">     * &lt;pre&gt;</em>
<a name="1682" href="#1682">1682</a> <em class="jxr_javadoccomment">     * Class com.acme.Foo was loaded via classloader 11111</em>
<a name="1683" href="#1683">1683</a> <em class="jxr_javadoccomment">     * ClassLoader tree: 11111 -&gt; 22222 (SYSTEM) -&gt; 33333 -&gt; BOOT </em>
<a name="1684" href="#1684">1684</a> <em class="jxr_javadoccomment">     * &lt;/pre&gt;</em>
<a name="1685" href="#1685">1685</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="1686" href="#1686">1686</a> <em class="jxr_javadoccomment">     * This method returns immediately if isDiagnosticsEnabled()</em>
<a name="1687" href="#1687">1687</a> <em class="jxr_javadoccomment">     * returns false.</em>
<a name="1688" href="#1688">1688</a> <em class="jxr_javadoccomment">     * </em>
<a name="1689" href="#1689">1689</a> <em class="jxr_javadoccomment">     * @param clazz is the class whose classloader + tree are to be</em>
<a name="1690" href="#1690">1690</a> <em class="jxr_javadoccomment">     * output.</em>
<a name="1691" href="#1691">1691</a> <em class="jxr_javadoccomment">     */</em>
<a name="1692" href="#1692">1692</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">void</strong> logClassLoaderEnvironment(Class clazz) {
<a name="1693" href="#1693">1693</a>         <strong class="jxr_keyword">if</strong> (!isDiagnosticsEnabled()) {
<a name="1694" href="#1694">1694</a>             <strong class="jxr_keyword">return</strong>;
<a name="1695" href="#1695">1695</a>         }
<a name="1696" href="#1696">1696</a>         
<a name="1697" href="#1697">1697</a>         <strong class="jxr_keyword">try</strong> {
<a name="1698" href="#1698">1698</a>             <em class="jxr_comment">// Deliberately use System.getProperty here instead of getSystemProperty; if</em>
<a name="1699" href="#1699">1699</a>             <em class="jxr_comment">// the overall security policy for the calling application forbids access to</em>
<a name="1700" href="#1700">1700</a>             <em class="jxr_comment">// these variables then we do not want to output them to the diagnostic stream. </em>
<a name="1701" href="#1701">1701</a>             logDiagnostic(<span class="jxr_string">"[ENV] Extension directories (java.ext.dir): "</span> + System.getProperty(<span class="jxr_string">"java.ext.dir"</span>));
<a name="1702" href="#1702">1702</a>             logDiagnostic(<span class="jxr_string">"[ENV] Application classpath (java.class.path): "</span> + System.getProperty(<span class="jxr_string">"java.class.path"</span>));
<a name="1703" href="#1703">1703</a>         } <strong class="jxr_keyword">catch</strong>(SecurityException ex) {
<a name="1704" href="#1704">1704</a>             logDiagnostic(<span class="jxr_string">"[ENV] Security setting prevent interrogation of system classpaths."</span>);
<a name="1705" href="#1705">1705</a>         }
<a name="1706" href="#1706">1706</a>         
<a name="1707" href="#1707">1707</a>         String className = clazz.getName();
<a name="1708" href="#1708">1708</a>         ClassLoader classLoader;
<a name="1709" href="#1709">1709</a>         
<a name="1710" href="#1710">1710</a>         <strong class="jxr_keyword">try</strong> {
<a name="1711" href="#1711">1711</a>             classLoader = getClassLoader(clazz);
<a name="1712" href="#1712">1712</a>         } <strong class="jxr_keyword">catch</strong>(SecurityException ex) {
<a name="1713" href="#1713">1713</a>             <em class="jxr_comment">// not much useful diagnostics we can print here!</em>
<a name="1714" href="#1714">1714</a>             logDiagnostic(
<a name="1715" href="#1715">1715</a>                 <span class="jxr_string">"[ENV] Security forbids determining the classloader for "</span> + className);
<a name="1716" href="#1716">1716</a>             <strong class="jxr_keyword">return</strong>;
<a name="1717" href="#1717">1717</a>         }
<a name="1718" href="#1718">1718</a> 
<a name="1719" href="#1719">1719</a>         logDiagnostic(
<a name="1720" href="#1720">1720</a>             <span class="jxr_string">"[ENV] Class "</span> + className + <span class="jxr_string">" was loaded via classloader "</span>
<a name="1721" href="#1721">1721</a>             + objectId(classLoader));
<a name="1722" href="#1722">1722</a>         logHierarchy(<span class="jxr_string">"[ENV] Ancestry of classloader which loaded "</span> + className + <span class="jxr_string">" is "</span>, classLoader);
<a name="1723" href="#1723">1723</a>     }
<a name="1724" href="#1724">1724</a> 
<a name="1725" href="#1725">1725</a>     <em class="jxr_javadoccomment">/**</em>
<a name="1726" href="#1726">1726</a> <em class="jxr_javadoccomment">     * Logs diagnostic messages about the given classloader</em>
<a name="1727" href="#1727">1727</a> <em class="jxr_javadoccomment">     * and it's hierarchy. The prefix is prepended to the message</em>
<a name="1728" href="#1728">1728</a> <em class="jxr_javadoccomment">     * and is intended to make it easier to understand the logs.</em>
<a name="1729" href="#1729">1729</a> <em class="jxr_javadoccomment">     * @param prefix </em>
<a name="1730" href="#1730">1730</a> <em class="jxr_javadoccomment">     * @param classLoader</em>
<a name="1731" href="#1731">1731</a> <em class="jxr_javadoccomment">     */</em>
<a name="1732" href="#1732">1732</a>     <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">void</strong> logHierarchy(String prefix, ClassLoader classLoader) {
<a name="1733" href="#1733">1733</a>         <strong class="jxr_keyword">if</strong> (!isDiagnosticsEnabled()) {
<a name="1734" href="#1734">1734</a>             <strong class="jxr_keyword">return</strong>;
<a name="1735" href="#1735">1735</a>         }
<a name="1736" href="#1736">1736</a>         ClassLoader systemClassLoader;
<a name="1737" href="#1737">1737</a>         <strong class="jxr_keyword">if</strong> (classLoader != <strong class="jxr_keyword">null</strong>) {
<a name="1738" href="#1738">1738</a>             <strong class="jxr_keyword">final</strong> String classLoaderString = classLoader.toString();
<a name="1739" href="#1739">1739</a>             logDiagnostic(prefix + objectId(classLoader) + <span class="jxr_string">" == '"</span> + classLoaderString + <span class="jxr_string">"'"</span>);
<a name="1740" href="#1740">1740</a>         }
<a name="1741" href="#1741">1741</a>         
<a name="1742" href="#1742">1742</a>         <strong class="jxr_keyword">try</strong> {
<a name="1743" href="#1743">1743</a>             systemClassLoader = ClassLoader.getSystemClassLoader();
<a name="1744" href="#1744">1744</a>         } <strong class="jxr_keyword">catch</strong>(SecurityException ex) {
<a name="1745" href="#1745">1745</a>             logDiagnostic(
<a name="1746" href="#1746">1746</a>                     prefix + <span class="jxr_string">"Security forbids determining the system classloader."</span>);
<a name="1747" href="#1747">1747</a>             <strong class="jxr_keyword">return</strong>;
<a name="1748" href="#1748">1748</a>         }        
<a name="1749" href="#1749">1749</a>         <strong class="jxr_keyword">if</strong> (classLoader != <strong class="jxr_keyword">null</strong>) {
<a name="1750" href="#1750">1750</a>             StringBuffer buf = <strong class="jxr_keyword">new</strong> StringBuffer(prefix + <span class="jxr_string">"ClassLoader tree:"</span>);
<a name="1751" href="#1751">1751</a>             <strong class="jxr_keyword">for</strong>(;;) {
<a name="1752" href="#1752">1752</a>                 buf.append(objectId(classLoader));
<a name="1753" href="#1753">1753</a>                 <strong class="jxr_keyword">if</strong> (classLoader == systemClassLoader) {
<a name="1754" href="#1754">1754</a>                     buf.append(<span class="jxr_string">" (SYSTEM) "</span>);
<a name="1755" href="#1755">1755</a>                 }
<a name="1756" href="#1756">1756</a> 
<a name="1757" href="#1757">1757</a>                 <strong class="jxr_keyword">try</strong> {
<a name="1758" href="#1758">1758</a>                     classLoader = classLoader.getParent();
<a name="1759" href="#1759">1759</a>                 } <strong class="jxr_keyword">catch</strong>(SecurityException ex) {
<a name="1760" href="#1760">1760</a>                     buf.append(<span class="jxr_string">" --&gt; SECRET"</span>);
<a name="1761" href="#1761">1761</a>                     <strong class="jxr_keyword">break</strong>;
<a name="1762" href="#1762">1762</a>                 }
<a name="1763" href="#1763">1763</a> 
<a name="1764" href="#1764">1764</a>                 buf.append(<span class="jxr_string">" --&gt; "</span>);
<a name="1765" href="#1765">1765</a>                 <strong class="jxr_keyword">if</strong> (classLoader == <strong class="jxr_keyword">null</strong>) {
<a name="1766" href="#1766">1766</a>                     buf.append(<span class="jxr_string">"BOOT"</span>);
<a name="1767" href="#1767">1767</a>                     <strong class="jxr_keyword">break</strong>;
<a name="1768" href="#1768">1768</a>                 }
<a name="1769" href="#1769">1769</a>             }
<a name="1770" href="#1770">1770</a>             logDiagnostic(buf.toString());
<a name="1771" href="#1771">1771</a>         }
<a name="1772" href="#1772">1772</a>     }
<a name="1773" href="#1773">1773</a> 
<a name="1774" href="#1774">1774</a>     <em class="jxr_javadoccomment">/**</em>
<a name="1775" href="#1775">1775</a> <em class="jxr_javadoccomment">     * Returns a string that uniquely identifies the specified object, including</em>
<a name="1776" href="#1776">1776</a> <em class="jxr_javadoccomment">     * its class.</em>
<a name="1777" href="#1777">1777</a> <em class="jxr_javadoccomment">     * &lt;p&gt;</em>
<a name="1778" href="#1778">1778</a> <em class="jxr_javadoccomment">     * The returned string is of form "classname@hashcode", ie is the same as</em>
<a name="1779" href="#1779">1779</a> <em class="jxr_javadoccomment">     * the return value of the Object.toString() method, but works even when</em>
<a name="1780" href="#1780">1780</a> <em class="jxr_javadoccomment">     * the specified object's class has overidden the toString method.</em>
<a name="1781" href="#1781">1781</a> <em class="jxr_javadoccomment">     * </em>
<a name="1782" href="#1782">1782</a> <em class="jxr_javadoccomment">     * @param o may be null.</em>
<a name="1783" href="#1783">1783</a> <em class="jxr_javadoccomment">     * @return a string of form classname@hashcode, or "null" if param o is null.</em>
<a name="1784" href="#1784">1784</a> <em class="jxr_javadoccomment">     * @since 1.1</em>
<a name="1785" href="#1785">1785</a> <em class="jxr_javadoccomment">     */</em>
<a name="1786" href="#1786">1786</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> String objectId(Object o) {
<a name="1787" href="#1787">1787</a>         <strong class="jxr_keyword">if</strong> (o == <strong class="jxr_keyword">null</strong>) {
<a name="1788" href="#1788">1788</a>             <strong class="jxr_keyword">return</strong> <span class="jxr_string">"null"</span>;
<a name="1789" href="#1789">1789</a>         } <strong class="jxr_keyword">else</strong> {
<a name="1790" href="#1790">1790</a>             <strong class="jxr_keyword">return</strong> o.getClass().getName() + <span class="jxr_string">"@"</span> + System.identityHashCode(o);
<a name="1791" href="#1791">1791</a>         }
<a name="1792" href="#1792">1792</a>     }
<a name="1793" href="#1793">1793</a> 
<a name="1794" href="#1794">1794</a>     <em class="jxr_comment">// ----------------------------------------------------------------------</em>
<a name="1795" href="#1795">1795</a>     <em class="jxr_comment">// Static initialiser block to perform initialisation at class load time.</em>
<a name="1796" href="#1796">1796</a>     <em class="jxr_comment">//</em>
<a name="1797" href="#1797">1797</a>     <em class="jxr_comment">// We can't do this in the class constructor, as there are many </em>
<a name="1798" href="#1798">1798</a>     <em class="jxr_comment">// static methods on this class that can be called before any</em>
<a name="1799" href="#1799">1799</a>     <em class="jxr_comment">// LogFactory instances are created, and they depend upon this</em>
<a name="1800" href="#1800">1800</a>     <em class="jxr_comment">// stuff having been set up.</em>
<a name="1801" href="#1801">1801</a>     <em class="jxr_comment">//</em>
<a name="1802" href="#1802">1802</a>     <em class="jxr_comment">// Note that this block must come after any variable declarations used</em>
<a name="1803" href="#1803">1803</a>     <em class="jxr_comment">// by any methods called from this block, as we want any static initialiser</em>
<a name="1804" href="#1804">1804</a>     <em class="jxr_comment">// associated with the variable to run first. If static initialisers for</em>
<a name="1805" href="#1805">1805</a>     <em class="jxr_comment">// variables run after this code, then (a) their value might be needed</em>
<a name="1806" href="#1806">1806</a>     <em class="jxr_comment">// by methods called from here, and (b) they might *override* any value</em>
<a name="1807" href="#1807">1807</a>     <em class="jxr_comment">// computed here!</em>
<a name="1808" href="#1808">1808</a>     <em class="jxr_comment">//</em>
<a name="1809" href="#1809">1809</a>     <em class="jxr_comment">// So the wisest thing to do is just to place this code at the very end</em>
<a name="1810" href="#1810">1810</a>     <em class="jxr_comment">// of the class file.</em>
<a name="1811" href="#1811">1811</a>     <em class="jxr_comment">// ----------------------------------------------------------------------</em>
<a name="1812" href="#1812">1812</a> 
<a name="1813" href="#1813">1813</a>     <strong class="jxr_keyword">static</strong> {
<a name="1814" href="#1814">1814</a>         <em class="jxr_comment">// note: it's safe to call methods before initDiagnostics (though</em>
<a name="1815" href="#1815">1815</a>         <em class="jxr_comment">// diagnostic output gets discarded).</em>
<a name="1816" href="#1816">1816</a>         thisClassLoader = getClassLoader(LogFactory.<strong class="jxr_keyword">class</strong>);
<a name="1817" href="#1817">1817</a>         initDiagnostics();
<a name="1818" href="#1818">1818</a>         logClassLoaderEnvironment(LogFactory.<strong class="jxr_keyword">class</strong>);
<a name="1819" href="#1819">1819</a>         factories = createFactoryStore();
<a name="1820" href="#1820">1820</a>         <strong class="jxr_keyword">if</strong> (isDiagnosticsEnabled()) {
<a name="1821" href="#1821">1821</a>             logDiagnostic(<span class="jxr_string">"BOOTSTRAP COMPLETED"</span>);
<a name="1822" href="#1822">1822</a>         }
<a name="1823" href="#1823">1823</a>     }
<a name="1824" href="#1824">1824</a> }
</pre>
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